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The_BPP
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What is the point in 192kHz?
      #239674 - 20/01/06 09:42 AM
I've just read SoS's excellent article on recording The Darkness' new album. I noticed, with interest, that once the tracks were recorded using analogue tape, it was edited in Pro Tools at 96kHz.

Now, correct me if I'm wrong, but, there seemed to be no hint of compromise in the production of the album, and yet they didn't use 192kHz...

So, what is the point in 192k?

Is it just case of "Hi-spec for Hi-Spec's sake", to fool naive punters into upgrading their soundcards?

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Peter Conz Connelly
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239678 - 20/01/06 09:44 AM
No, this is not the case, but I'm sure someone with more technical know how than me will elaborate...

P


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The_BPP
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Re: What is the point in 192kHz? new [Re: Peter Conz Connelly]
      #239679 - 20/01/06 09:49 AM
Well, recording using 96kHz will reproduce frequencies of over 40kHz - more than twice the human theoretical hearing range, and well above any frequency which could potentially modulate sounds within our hearing range, so I'd like to hear what the justification of 192kHz is.

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Steve Hill
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239684 - 20/01/06 09:55 AM
This could be a long thread. Personally I've yet to hear any justification for 192k that convinces me, but maybe I've got cloth ears as a (very) few people claim to be able to hear a difference.

Since decent analogue kit will comfortably go up to 192k and way beyond, actually dropping it into PT or any digital domain for editing could even be argued (by some) to be a retrograde step!!

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The_BPP
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Re: What is the point in 192kHz? new [Re: Steve Hill]
      #239687 - 20/01/06 10:00 AM
True indeed.

My point is, if the Darkness wanted 192kHz, they would have used it. They did not.

If they choose not to use it, then why should the lower-budgeted, hard-disk-space-conscious producers entertain the idea of 192k?

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Michael Harrison
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239694 - 20/01/06 10:12 AM
Dan Lavry (who makes very pukka Lavry ADCs & DACs) argues quite strongly that current materials/manufacturing technology/whatever are limiting what can feasibly be achieved with increasing sample rates octave upon octave (as we are).

I think that the current crop of options available (I'm still using 24bit 44.1kHz!!) are 'good enough' for the moment - I feel there's other areas of our game which could do with development & improvement before further increases of sample rate yield significant benefits, even ignoring the possibility they may not be capturing all that they claim...

Mike

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The Byre



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239703 - 20/01/06 10:21 AM
Hugh RJ has written extensively, both on this and the older forums ands in the magazine, on this subject. This is a subect that he has explained with clarity and insight and I suggest to one and all that they read his articles.

Without going into details which are easily looked up in the back issues and on the first and the second forums, good low-res is far better than poor hi-def.

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Grimm Reaper Sound
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239706 - 20/01/06 10:25 AM
Some claim that phsycho-acoustics come into play at very high frequencies and that even if we don't hear past 20k, humans perceive frequencies well into the 40k and on past 60k.

When I think about this from a more practical point of view, going from say 20k up to 80k is just 2 octaves. Now 2 octaves is now a far stretch for the ears. We can easily perceive beating from tones that are 2 octaves apart but lower in the frequency spectrum. Why wouldn't the same thing apply higher up the scale.

This brings me to another point, get two signals, one at 65k the other at 75k...mix them...you get sum and difference signals (sometimes known as "beating" or "aliasing")...the difference is 10k, well within perceptable range... This is how AM radio works folks, but with a much higher frequency "carrier" signal.

As for why they used 96k instead of 192k...maybe they only had 96k converters available with them at the time.


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Anonymous
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Re: What is the point in 192kHz? new [Re: Grimm Reaper Sound]
      #239714 - 20/01/06 10:37 AM
Let's face it, even 96kHz was completely wasted on that project! They can't've been that bothered about quality if they stuck everything through Protools - though it's about all the "music" deserved.

On a slightly more serious note, the high sample rate issue is about so much more than mere frequency response or just the digital side of things. As The Byre said, it's been discussed at length on these forums; try a search of this forum, the old Infopo (V2) forum and the main SOS site.


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narcoman
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239718 - 20/01/06 10:41 AM
aaaah yes, grim, but sum and difference tones ARE all captured within current technologies.

And to counter an earlier point - there may be SOME individuals who (dubiously in my books) claim to hear detail in larger rate samples - however they are the occasional and most think digital radio is good quality....

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Michael Harrison
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Re: What is the point in 192kHz? new [Re: ]
      #239729 - 20/01/06 10:50 AM
Quote 0VU:

Let's face it, even 96kHz was completely wasted on that project! They can't've been that bothered about quality if they stuck everything through Protools - though it's about all the "music" deserved.






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James PerrettModerator



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239731 - 20/01/06 10:51 AM
No-one has convincingly proven that humans can hear much beyond 20kHz (the one Japanese study that claimed to show this has since been discredited).

However, many people claim to hear differences with gear that works at 192kHz. I wouldn't necessarily put this down to the sample rate - there are other factors which may be affecting the signal in the normally audible frequency range.

Cheers

James.

PS - I know that one of 0VU's mastering friends thinks that 384kHz is only just about comparable to analogue!

--------------------
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Edited by James Perrett (20/01/06 10:53 AM)


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Anonymous
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Re: What is the point in 192kHz? new [Re: James Perrett]
      #239735 - 20/01/06 10:57 AM
Quote:


PS - I know that one of 0VU's mastering friends thinks that 384kHz is only just about comparable to analogue!




Lol Who've you been talking to?

Several of them do Some feel that it still isn't good enough

We don't necessarily agree about everything

Good analogue still sounds nicer than even good digital though. Not necessarily better, just nicer. Which is fine if you're looking for a nice sound. Sometimes accurate is better - and 384 is pretty accurate - though perhaps not as accurate as 176.4. Or even 88.2. Too many variables.

I'm going back to listening to the tape I'm supposed to be working on next week. Full track mono 1/4" recorded in 1959


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Humphreysbogort



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239739 - 20/01/06 11:07 AM
a guy came into where i used to work wanting to transfer all his vinyl at 192khz. When i enquired why he wanted to do this he said that "I had to hear the quality to believe it"

I explained to hime that when vinyl is mastered there is a pretty steep roll off above 16khz as anything above that would cause the needle to jump out of the groove on the record. I said that sampling so high would merely highlight the limitations of the source.

This guy was about 65 and probably therefore couldnt hear much above 13khz anyway...

However he still insisted that he could hear the difference. when i showed him something done at 48khz. Where i could not.

Obviosly he had read somwhere that this was the thing to do.

The moral of this story is that if somebody reads something in "what HI-FI" etc they tend to believe it.

In my opinion things like 192khz are used to sell expensive gear to people who are too ignorant of the actual physics of audio to know any better.

just my 2c


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Anonymous
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Re: What is the point in 192kHz? new [Re: Humphreysbogort]
      #239745 - 20/01/06 11:12 AM
Quote:

The moral of this story is that if somebody reads something in "what HI-FI" etc they tend to believe it.





Perhaps. Or perhaps the moral is, you do it and charge him for a high resolution transfer instead of an ordinary one, he goes away happy in his belief and you go away happy with a few extra quid in your pocket and your belief in his stupidity reinforced.

If you get a lot of that kind of work you might want to upgrade your cables too. And perhaps take on an agency for one of the more esoteric cable brands.

Cynical exploitation? Me?


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feline1
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239752 - 20/01/06 11:20 AM
It does seem a shame as let's face it,
some of the Darkness's best stuff is doubtless happening up above 80kHz
I for one would rather hear them up there than their 20 - 20kHz output

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Martin: the return.....



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Re: What is the point in 192kHz? new [Re: Humphreysbogort]
      #239758 - 20/01/06 11:25 AM
Quote narpin99:


In my opinion things like 192khz are used to sell expensive gear to people who are too ignorant of the actual physics of audio to know any better.





It's certainly true that there's a lot of BS abroad in the hifi world to hook in the gullible.

On the other hand, there are a number of extremely non-gullible professionals who are convinced by it (like Elliot Mazer) simply because they think it sounds better.

I think there's a moral here - whatever the technical arguments for and against, if you test 192KHz and you genuinely think it improves your sound, then go for it. You shouldnt need technical arguments to confirm or contradict what your ears are telling you.

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ghellquist



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239760 - 20/01/06 11:26 AM
Well, my two cents. You simply have to try with your own equipment.

In a perfect world 44.1kHz is perfect up to about 20kHz. And 96 is, well, even more perfect? Not to talk about 192 that should be, well, even more perfect again?

Reality seems to be different. Somehow the limitations in AD and DA converters and processing plugins and such make the sounds different. And most probably, there is an optimum frequency for every combination. Not necessarily the fastest the boxes can go.

What I would expect from real world converters is that with a higher sample rate I would get slightly increased distortion. And as every tape fan knows, distortion can make things sound nicer.

Personally, I go at 44.1 using Lavry Blues. To put it short, the sample rate is not the limiting factor in my recordings. Maybe in 20 years time when my mic positioning is perfect... (I do mostly on location classical music thoung, guess that is less demanding than distorted electrical guitars).

Gunnar


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The_BPP
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Re: What is the point in 192kHz? new [Re: feline1]
      #239764 - 20/01/06 11:28 AM
Well, there you have it - SoS forums in a nutshell... We start off with a technical discussion, and end up slagging-off "The Darkness".

On that particular tangent, I quite like 'em. Although, their current album is mastered with the loudness knob set to number 11. Taking their Spinal Tap comparision a step too far, they've definately gone "One Louder".


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Barish
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239776 - 20/01/06 11:49 AM
If you want to discuss the necessity of 192kHz sampling, I guess you need to read Dan's white paper on Sampling Theory first. It's quite sobering:

http://www.lavryengineering.com/documents/Sampling_Theory.pdf

B.


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Tomás Mulcahy
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Re: What is the point in 192kHz? new [Re: feline1]
      #239781 - 20/01/06 12:01 PM
Quote feline1:

It does seem a shame as let's face it,
some of the Darkness's best stuff is doubtless happening up above 80kHz
I for one would rather hear them up there than their 20 - 20kHz output




LOL!

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Grimm Reaper Sound
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One last technical point before the entire thread breaks down new [Re: The_BPP]
      #239822 - 20/01/06 01:16 PM
Most people tend to forget what it takes to make 196k ADC's. To make a premium quality 196k ADC, one must have extremely fast sample and hold circuitry. This circuitry makes sampling of square waves of much higher "fidelity". Square waves are the "Primo" source of harmonics.

This is why top quality analog is so much better than ordinary digital. But getting into "extreme" sampling rates enhances the ability to capture that gnarly square wave. Which in turn gets you higher up the fidelity scale.

I for one would love to see 1Mhz sampling rates, but then again you could buy top quality analog and get that.


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Steve Hill]
      #239823 - 20/01/06 01:17 PM
Quote Steve Hill:

Since decent analogue kit will comfortably go up to 192k and way beyond...




Some analogue electronics are wideband and will pass frequencies of 100kHz or more. However, I'm yet to find an analogue tape recorder that can do much better than 50kHz

hugh

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Hugh RobjohnsAdministrator
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Re: One last technical point before the entire thread breaks down new [Re: Grimm Reaper Sound]
      #239831 - 20/01/06 01:29 PM
Quote Grimm Reaper Sound:

Square waves are the "Primo" source of harmonics.




A square wave is created from a continuous series of odd harmonics at specific relative amplitudes. Great if you like odd harmonics. Bugger all use if you want something a little kinder on the ears

Quote:

But getting into "extreme" sampling rates enhances the ability to capture that gnarly square wave. Which in turn gets you higher up the fidelity scale.

I for one would love to see 1Mhz sampling rates, but then again you could buy top quality analog and get that.




Er... I fear this shows the all-too-common misunderstanding of sampling theory and the inherent bandwidth limitations of analogue equipment.

hugh

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Barish
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Re: One last technical point before the entire thread breaks down new [Re: Grimm Reaper Sound]
      #239884 - 20/01/06 02:34 PM
Quote Grimm Reaper Sound:

Most people tend to forget what it takes to make 196k ADC's. To make a premium quality 196k ADC, one must have extremely fast sample and hold circuitry. This circuitry makes sampling of square waves of much higher "fidelity". Square waves are the "Primo" source of harmonics.

This is why top quality analog is so much better than ordinary digital. But getting into "extreme" sampling rates enhances the ability to capture that gnarly square wave. Which in turn gets you higher up the fidelity scale.

I for one would love to see 1Mhz sampling rates, but then again you could buy top quality analog and get that.




You obviously have next to zero knowledge about the basics of sampling. Why don't you scroll a few posts up from yours and read my post and the document linked there first? That would help people avoid reading posts like yours that are full of nonsense rubbish.

I'll quote that message of mine here for your convenience:

Quote Barish:

If you want to discuss the necessity of 192kHz sampling, I guess you need to read Dan's white paper on Sampling Theory first. It's quite sobering:

http://www.lavryengineering.com/documents/Sampling_Theory.pdf

B.




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Stan



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239911 - 20/01/06 03:17 PM
IMO unless you have very poor hearing, you will clearly hear the difference between recordings made at 44.1 and 192kHz.
That said, I still very much appreciate the 16bit 44.1kHz CD format and would hate to loose it now that we 'own' it, so to speak.

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Marky
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Re: One last technical point before the entire thread breaks down new [Re: Hugh Robjohns]
      #239915 - 20/01/06 03:26 PM
Quote Hugh Robjohns:


A square wave is created from a continuous series of odd harmonics at specific relative amplitudes. Great if you like odd harmonics. Bugger all use if you want something a little kinder on the ears

Quote:

But getting into "extreme" sampling rates enhances the ability to capture that gnarly square wave. Which in turn gets you higher up the fidelity scale.




hugh




And perfect square waves, with an infinite bandwidth of odd harmonmics don't even exist .. therefore the square wave argument is not valid.

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Mr DiBergi



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Re: What is the point in 192kHz? new [Re: Barish]
      #239934 - 20/01/06 03:58 PM
Quote Barish:

If you want to discuss the necessity of 192kHz sampling, I guess you need to read Dan's white paper on Sampling Theory first. It's quite sobering:

http://www.lavryengineering.com/documents/Sampling_Theory.pdf

B.




Thanks for the link Barish, very interesting stuff.

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James PerrettModerator



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #239941 - 20/01/06 04:14 PM
There are plenty of ADC's that will do 1MHz - and the editing software that I use will work up to 10MHz but the trick is getting them to work together

Cheers

James.

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beauregard
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Re: What is the point in 192kHz? new [Re: Grimm Reaper Sound]
      #239951 - 20/01/06 04:35 PM
Hello,

This is a question, not an argument

Whenever I read arguments for high sampling rates (> 48k, say) that are based on the high-frequency-content's production of artifacts in the audible range I become confused. Wouldn't the artifactual information be present in the signal if it were recorded at a lower samplr rate, even if the higher frequency components that produced it weren't? Isn't this also why we can hear the artifactual information in the first place?

I have a feeling that there is a simple answer to my confusion that I am just not getting. Enliightment would be much appreciated!

Regards


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Barish
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Re: What is the point in 192kHz? new [Re: Stan]
      #239977 - 20/01/06 05:22 PM
Quote Stan:

IMO unless you have very poor hearing, you will clearly hear the difference between recordings made at 44.1 and 192kHz.
That said, I still very much appreciate the 16bit 44.1kHz CD format and would hate to loose it now that we 'own' it, so to speak.




I'm not sure you have read Dan's white paper before making a comment on this.

I'd like to remind you that he is one of the people who design and produce the AD/DA converters so that we can buy and use them in order to make comments as such, not to mention that he also happens to be a musician himself and the converters he designs and manufactures are right up there with the best available on this planet.

Please read the following and then make a comment, which is going to have to be as scientific as his in order to stand. Otherwise, it will have to remain subjective/your personal preference and not something scientifically accurate:

Quote Dan Lavry:

There are reports of better sound with higher sampling rates. No doubt, the folks that like the "sound of a 192KHz" converter hear something. Clearly it has nothing to do with more bandwidth: the instruments make next to no 96KHz sound, the microphones don't respond to it, the speakers don't produce it, and the ear can not hear it.


Moreover, we hear some reports about "some of that special quality captured by that 192KHz is retained when down sampling to 44.1KHz. Such reports neglect the fact that a 44.1KHz sampled material can not contain above 22.05KHz of audio.


Some claim that that 192K is closer to the audio tape. That same tape that typically contains "only" 20KHz of audio gets converted to digital by a 192K AD, than stripped out of all possible content above 22KHz (down sample to CD).


“If you hear it, there is something there” is an artistic statement. If you like it and want to use it, go ahead. But whatever you hear is not due to energy above audio. All is contained within the "lower band". It could be certain type of distortions that sound good to you. Can it be that someone made a real good 192KHz device, and even after down sampling it has fewer distortions? Not likely. The same converter architecture can be optimized for slower rates and with more time to process it should be more accurate (less distortions).


The danger here is that people who hear something they like may associate better sound with faster sampling, wider bandwidth, and higher accuracy. This indirectly implies that lower rates are inferior. Whatever one hears on a 192KHz system can be introduced into a 96KHz system, and much of it into lower sampling rates. That includes any distortions associated with 192KHz gear, much of which is due to insufficient time to achieve the level of accuracy of slower sampling.


Conclusion:


There is an inescapable tradeoff between faster sampling on one hand and a loss of accuracy, increased data size and much additional processing requirement on the other hand.
AD converter designers can not generate 20 bits at MHz speeds, yet they often utilize a circuit yielding a few bits at MHz speeds as a step towards making many bits at lower speeds.


The compromise between speed and accuracy is a permanent engineering and scientific reality.


Sampling audio signals at 192KHz is about 3 times faster than the optimal rate. It compromises the accuracy which ends up as audio distortions.


While there is no up side to operation at excessive speeds, there are further disadvantages:


1. The increased speed causes larger amount of data (impacting data storage and data transmission speed requirements).


2. Operating at 192KHz causes a very significant increase in the required processing power, resulting in very costly gear and/or further compromise in audio quality.


The optimal sample rate should be largely based on the required signal bandwidth. Audio industry salesman have been promoting faster than optimal rates. The promotion of such ideas is based on the fallacy that faster rates yield more accuracy and/or more detail. Whether motivated by profit or ignorance, the promoters, leading the industry in the wrong direction, are stating the opposite of what is true.


Sampling Theory Page 26
Copyright Dan Lavry, Lavry Engineering, Inc, 2004




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dubbmann
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #240016 - 20/01/06 06:32 PM
barish, thanks for the reference. i started a thread with similar thoughts last summer, and was appalled at the level of misinformation people were spouting like gospel. ("ignorance is not impediment to utterance" a wise man once said). by the time most rockers hit their late 20s, their hearing limit is creeping downn to 10 kHz. read pete townsend's recent warnings to people using ipods for the danger of headphones...

this reminds me of the vinyl purists who disdain cds. i've often wanted to add some surface noise to a cd's output and a/b w/ vinyl to these folks. (before i'm flamed on this, let me add: *if* you have b&w 801s, mark levinson amps, bryston pre-amps, a perfect listening space - oh hell, flame away, most of us *still* won't hear the difference!)

anyway, i suppose we should hope that there are enough technology-philes to buy the latest and greatest, hence keeping the manufacturers going. not least because then the luddites among us (call me ned ludd, to quote the late, great robert calvert) can buy killer product as it's discontinued and sold for pennies...

cheers,

d

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Stan



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Re: What is the point in 192kHz? new [Re: Barish]
      #240041 - 20/01/06 07:15 PM
Hi Barish, I trust you read Dan's white paper more carefully than my post.
I agree with Dan ''If you like it and want to use it, go ahead.''

Have you tried it yourself yet?

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Barish
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #240062 - 20/01/06 08:13 PM
Yes. It is different. But different does not necessarily mean "better". Differences are subject to many other conditions in design topology and you'll find that a 192I/O operated at 192kHz will sound different than a 96I/O operated at 192kHz, so will a Rosetta 800 or AD-16X/DA-16X or an RME or what have you. Even different products from same manufacturer sound different. That does not prove a point.

From a scientific point of view, a 192kHz sampling is not better than 96kHz for the audible frequency range in terms of fidelity to the original, and in fact, it is worse, as explained in that paper.

If it sounds better to "you", that's an artistic statement and electronic devices are not designed with artistic decisions, but rather mathematical calculations. We're only making an art using something that was designed with non-artistic values.

B.


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Stan



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Re: What is the point in 192kHz? new [Re: Barish]
      #240072 - 20/01/06 08:26 PM
This might be one reason why 192kHz sounds so good.

The effect of oversampling and noise shaping on quantisation noise in A/D conversion.
If you expand the range of frequencies that can pass through the system by sampling more quickly, more and more of the noise shaping (dither) can be filtered into higher frequency bands that can not be heard.

Paul Frindle of Sony Professional stated in an interview in 1998 that it was easier to make agood converter at 96kHz than at 48kHz.
I take it from this a 192kHz converter has some advantages for the manufacturer as well.

Edited by Stan (20/01/06 08:39 PM)


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Richard Steed
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Re: One last technical point before the entire thread breaks down new [Re: Barish]
      #240091 - 20/01/06 08:55 PM
Quote Barish:

Quote Grimm Reaper Sound:

Most people tend to forget what it takes to make 196k ADC's. To make a premium quality 196k ADC, one must have extremely fast sample and hold circuitry. This circuitry makes sampling of square waves of much higher "fidelity". Square waves are the "Primo" source of harmonics.

This is why top quality analog is so much better than ordinary digital. But getting into "extreme" sampling rates enhances the ability to capture that gnarly square wave. Which in turn gets you higher up the fidelity scale.

I for one would love to see 1Mhz sampling rates, but then again you could buy top quality analog and get that.




You obviously have next to zero knowledge about the basics of sampling. Why don't you scroll a few posts up from yours and read my post and the document linked there first? That would help people avoid reading posts like yours that are full of nonsense rubbish.

I'll quote that message of mine here for your convenience:

Quote Barish:

If you want to discuss the necessity of 192kHz sampling, I guess you need to read Dan's white paper on Sampling Theory first. It's quite sobering:

http://www.lavryengineering.com/documents/Sampling_Theory.pdf

B.






Well according to that Dan Lavry,he claims that the human ear can only pick up signals up to 40k and quotes that there is no need for a MHz audio system.PREPOSTEROUS.
Just listen to the very noticable difference in the quality of AM radio(in KHz) and FM(in Mhz).Surely he cant be saying we cant hear radio 1.I have to put up with the bloody thing every morning when my bloody sister wakes up.
Richard Steed
www.soundclick.com/steedie


--------------------
RSteed


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Wurlitzer
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Re: What is the point in 192kHz? new [Re: Grimm Reaper Sound]
      #240103 - 20/01/06 09:23 PM
Quote Grimm Reaper Sound:

When I think about this from a more practical point of view, going from say 20k up to 80k is just 2 octaves. Now 2 octaves is now a far stretch for the ears. We can easily perceive beating from tones that are 2 octaves apart but lower in the frequency spectrum. Why wouldn't the same thing apply higher up the scale?




I'm not sure I quite understand the technical nature of the "beating" you refer to, but maybe because the notes of the harmonic series get closer together as they get higher?

ie, two octaves above a fundamental note is the distance to its fourth harmonic. Two octaves above that brings you to its sixteenth harmonic, and so on. Thus the perception of difference between high notes is not the same as the perception of difference between low notes.

You can hear this if you play a chord at the top of the piano and then the same chord at the bottom of the piano. Any dissonances (or even thirds, which can be perceived as dissonance down there) or out of tune notes jump out and beat like all hell in the low version, whereas the ear is much more forgiving in the high version, since it picks up sypathetic resonances with the lower strings and appears as a group of overtones higher up the harmonic series (where such dissonances are more natural).

Again I'm not sure this is connected with what you meant. Just pointing out that the way we hear is not a straightforward linear scale up the frequency spectrum. An octave is a much smaller interval, in actual aural terms, down low than it is up high, since it is the distance between one or two harmonics rather than the distance between many.


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Andreas Bygdell



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Re: One last technical point before the entire thread breaks down new [Re: Richard Steed]
      #240108 - 20/01/06 09:37 PM
Quote Richard Steed:

yada yada



Classic.


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Grimm Reaper Sound
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Re: One last technical point before the entire thread breaks down new [Re: Barish]
      #240113 - 20/01/06 09:40 PM
Barish, I would check that document you so proudly keep bringing up and look at page 25...The reproduction of the square wave shown is BANDWIDTH LIMITED to 20kHz before hitting the converters...Obviously this works!
Yes his document is technically correct for the most part but some people can perceive a 40kHz filter being turned on in the signal path.

What I meant to say was that without bandwidth limiting and without bringing up data transfer rates for high frequency sampling and the inherent FIR limitations. You cannot reproduce a square wave in the digital domain like you have in analog.

As for the use of this in music, push two oscilator into high frequency (over 20kHz) mix them back together and start playing with that combined signal, you then get an idea of what is available as a difference signal. And yes some analog synths can do this.

So yes using 196kHz can get you better fidelity.

Check before roasting next time


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Richard Steed
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #240124 - 20/01/06 09:58 PM
There isnt really much of a significant and apparent difference though between 44.1 khz and 192khz.Obviously,there would be when audio is heard in Mhz.
Stick to 44.1 Khz i say.......'cause I do now-every morning,while I'm having my cornflakes.

--------------------
RSteed

Edited by Richard Steed (20/01/06 09:59 PM)


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bulley



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Re: One last technical point before the entire thread breaks down new [Re: Richard Steed]
      #240130 - 20/01/06 10:10 PM







Well according to that Dan Lavry,he claims that the human ear can only pick up signals up to 40k and quotes that there is no need for a MHz audio system.PREPOSTEROUS.
Just listen to the very noticable difference in the quality of AM radio(in KHz) and FM(in Mhz).Surely he cant be saying we cant hear radio 1.I have to put up with the bloody thing every morning when my bloody sister wakes up.
Richard Steed

is this a joke?


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Melodymann



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #240140 - 20/01/06 10:49 PM
Considering companies like Sony have released mobile phones with gigs of storage so people can play MP3'S I cant really see any need for more than 16 bit.
How many albumns have many of us got that have been mastered on tape?
I think there is a whole industry making money off the backs off home studio's.
What ever next?

--------------------
Child birth was painfull so dont waste your life being a slave chase those dreams and take a chance on happiness.


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Barish
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Re: One last technical point before the entire thread breaks down new [Re: Grimm Reaper Sound]
      #240505 - 21/01/06 06:09 PM
Quote Richard Steed:

Well according to that Dan Lavry,he claims that the human ear can only pick up signals up to 40k and quotes that there is no need for a MHz audio system.PREPOSTEROUS.
Just listen to the very noticable difference in the quality of AM radio(in KHz) and FM(in Mhz).Surely he cant be saying we cant hear radio 1.I have to put up with the bloody thing every morning when my bloody sister wakes up.
Richard Steed
www.soundclick.com/steedie







You are kidding right?

What's this? A kindergarten or something? How old are you? What are your electronic qualifications? Could you please tell me the difference between an AM radio signal and FM radio signal in terms of audio quality, apart from the frequency band content? Like for instance, why can AM only carry mono audio information as opposed to FM's stereo/mono compatibility etc?

Let me tell you this: The audio quality difference between AM and FM is not about the amount of carrier frequency, but rather about how the audio content is modulated onto the carrier frequency. Go read about it a bit more and then come back. I've spent 3 years in a technical school just to read that concept from ground up.

Quote Grimm Reaper Sound:

Barish, I would check that document you so proudly keep bringing up and look at page 25...The reproduction of the square wave shown is BANDWIDTH LIMITED to 20kHz before hitting the converters...Obviously this works!
Yes his document is technically correct for the most part but some people can perceive a 40kHz filter being turned on in the signal path.

What I meant to say was that without bandwidth limiting and without bringing up data transfer rates for high frequency sampling and the inherent FIR limitations. You cannot reproduce a square wave in the digital domain like you have in analog.

As for the use of this in music, push two oscilator into high frequency (over 20kHz) mix them back together and start playing with that combined signal, you then get an idea of what is available as a difference signal. And yes some analog synths can do this.

So yes using 196kHz can get you better fidelity.

Check before roasting next time




Some people? Who for example? Under what tests?

Well, I am Jesus Christ then. Worship me. Proof? Well, I know I am.

We're talking something scientific here, dude. Not hear-say. "Some people can perceive the changes in 40kHz." Yeah sure.

Even if we accepted that "some" people do perceive as high as 40kHz of audio, rather "super-audio" to us mortals, 80kHz sampling rate would sort that out with no problems.

I'm still not sure you're getting the point. The guy is saying "96kHz is more than enough. No need for 192".


Yours is like saying "let's capture ultraviolet and infrared light when filming as well, cos some people said that they didn't see them but perceived them."


That's nonsense.


This subject has been caned to death in its all entirety at Dan's forum at R/E/P for months, with contributions from many other manufacturer/mastering engineer people. I'm not going to waste any more time trying to explain it all over again here. Sorry. If you are so convinced then go buy the next 384kHz converters when they are out. Or if you are interested to know more about it, you can check it in Dan's own forum. He also has a forum at his website http://www.lavryengineering.com but that's totally Lavry product range related. R/E/P forum is general technical discussion.

B.


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Barish
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #240528 - 21/01/06 07:16 PM
In fact, below thread could be a good starter for you:

http://recforums.prosoundweb.com/index.php/t/2997/0

and this "high frequency transients fallacy":

http://recforums.prosoundweb.com/index.php/t/4097/0


and this "EQ for 192kHz sampling":

http://recforums.prosoundweb.com/index.php/t/2666/0




B.


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Stan



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Re: What is the point in 192kHz? new [Re: Barish]
      #240535 - 21/01/06 07:31 PM

I see and agree - most of the advantages of a higher sampler rate would indeed appear to be covered by sampling at 96kHz.
I'm also gathering that these sonic advantages are more to do with the converters and their 'ways' than the increased frequency range.

If I ever get the opportunity to record a great artists performance, I would like to be able to play safe and record it at 192kHz.
No harm in that is there?

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Wurlitzer
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Re: What is the point in 192kHz? new [Re: Stan]
      #240544 - 21/01/06 07:50 PM
Quote Stan:

If I ever get the opportunity to record a great artists performance, I would like to be able to play safe and record it at 192kHz.
No harm in that is there?




Only that you need to have invested in 192kHz converters to do it.

Then, whatever medium you're recording to, you need over four times as much storage space as you would to record at 44.1khz.

Then you need massively more CPU power for the same number of simultaneous tracks, and to consider whether you're pushing the stability of your system to the limit and thereby compromising the security of the session. Or if you're using a non-computer hard disk recorder, you need one with the spec and power to do that many tracks at 192khz.

Weighing all this up, you may find that it costs many, many times more money to be set up to record the session, and do so effectively, at 192 khz as it does at 44.1 khz. If the only person who can hear the difference is your dog, then that's the harm: you've spent a load of money and got no discernable improvement for it.

I'm not saying there's no difference - I don't have sufficient experience of higher sample rates to have settled on an opinion. All I'm saying is that IF there's no difference, then there's no point spending the money.


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Stan



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Re: What is the point in 192kHz? new [Re: Wurlitzer]
      #240559 - 21/01/06 08:25 PM
Good point Wurlitzer. I dont think I'd try it without a test flight.
My CPU is an AMD Athlon 2.8 so 192kHz mulititracking is not on the cards for me, yet.
Processors will get faster.
I can get impressive results stereo sampling at 192kHz with my E-mu 1212m.

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dubbmann
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #240930 - 22/01/06 06:25 PM
barish, take heart and know you fought the good fight. there are some people who will not be convined no matter what technical details you present.

when i last had this argument a few months ago with individuals who i'll leave unnamed, i got so disgusted with their ignorance that i went on the web and found a whole set of college lecture notes available online concerning electrical and communications engineering, from M.I.T. (Massechusetts Institute of Technology, #1 US university in science and engineering.) these notes covered all the stuff in the white paper you cited, but in much more detail, startingn with the nyquist sampling theorem, etc. i was going to post the urls on the particular forum.

then i remembered what a friend had taught me many years ago: you can lead a whore to culture but you can't make her think. so i dropped the matter. i only chimed in on your thread cause i wanted to show solidarity, not in any hope of educating the yahoos (read gulliver's travels for the original reference). that and do what i do: buy up end-of-life kit that *only* does 44.1/16. thanks to the punters who buy the latest gear, i can equip a pentium 3 pc with a pro audio sound for pennies. in my home studio i've got 7 machines linked by adat optical, running reason and assorted vst instruments, all connected by fast ethernet switching fabric. total cost, pcs, soundcards,etc? under 500 pounds.

btw, i dig kebabs!

cheers,

d

--------------------
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http://www.phichibe.com


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Grimm Reaper Sound
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Re: One last technical point before the entire thread breaks down new [Re: Barish]
      #240956 - 22/01/06 07:22 PM
Here is a direct copy from the SOS July 1998 issue.
CD: The Next Generation: Super Audio Compact Disc

"
The Sony/Philips proposed hybrid disc format does not store high-resolution audio data in the conventional multi-bit Pulse Code Modulation form (PCM) used in current digital recording systems. Instead it uses a process known as Direct Stream Digital (DSD), upon which Sony have been working for some time, as a new recording, mastering and archiving format.

DSD is claimed to provide an audio bandwidth between DC and 100kHz and a realisable dynamic range well in excess of 120dB (the signal-to-noise ratio is specified as better than -120dBFS at 20kHz and the equivalent audio resolution better than 24 bits). Sony and Philips have been fine-tuning the system over recent months through extensive listening and comparative sessions held around the world, with numerous artists, producers, recording and mastering engineers, and even audiophile consumers, taking part.
.
.
Current DSD systems sample audio at 2.8224 MHz (that is, 64 x 44.1kHz) and the resulting 1-bit data stream is obviously pretty big. However, it is actually 'only' four times bigger than that of a conventional 16-bit/44.1kHz PCM signal, and so is well within the capabilities of many current tape and disk recording systems -- Sony are using PCM800 (DTRS format) machines with a custom interface for experimental DSD work in the UK, and in America commercial stereo DSD recordings are being made on hard disk-based recorders (Sonic Solutions manufacture a compatible system, for example).
"


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Celsius
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Re: One last technical point before the entire thread breaks down new [Re: Grimm Reaper Sound]
      #240974 - 22/01/06 08:07 PM
Quote Grimm Reaper Sound:

.

So yes using 196kHz can get you better fidelity.





What kind of speakers would I need to get the full
benefit from this increased fidelity?

--------------------
Phatcat Studios--"I love the smell of Genelecs in the morning"


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Barish
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Re: One last technical point before the entire thread breaks down new [Re: Grimm Reaper Sound]
      #241078 - 22/01/06 11:31 PM
Quote Grimm Reaper Sound:

Here is a direct copy from the SOS July 1998 issue.
CD: The Next Generation: Super Audio Compact Disc

"
The Sony/Philips proposed hybrid disc format does not store high-resolution audio data in the conventional multi-bit Pulse Code Modulation form (PCM) used in current digital recording systems. Instead it uses a process known as Direct Stream Digital (DSD), upon which Sony have been working for some time, as a new recording, mastering and archiving format.

DSD is claimed to provide an audio bandwidth between DC and 100kHz and a realisable dynamic range well in excess of 120dB (the signal-to-noise ratio is specified as better than -120dBFS at 20kHz and the equivalent audio resolution better than 24 bits). Sony and Philips have been fine-tuning the system over recent months through extensive listening and comparative sessions held around the world, with numerous artists, producers, recording and mastering engineers, and even audiophile consumers, taking part.
.
.
Current DSD systems sample audio at 2.8224 MHz (that is, 64 x 44.1kHz) and the resulting 1-bit data stream is obviously pretty big. However, it is actually 'only' four times bigger than that of a conventional 16-bit/44.1kHz PCM signal, and so is well within the capabilities of many current tape and disk recording systems -- Sony are using PCM800 (DTRS format) machines with a custom interface for experimental DSD work in the UK, and in America commercial stereo DSD recordings are being made on hard disk-based recorders (Sonic Solutions manufacture a compatible system, for example).
"





That text talks about a technology when it was a baby and everything mentioned there were yet to be proven, and it is based on a press release by the developers 8 years ago. EIGHT YEARS AGO. You can not find many people on these boards who still use a professional digital audio product that they bought eight years ago. As a non-native speaker of English language, I can even see that when I read it and I am deeply disappointed that you could not see what I see in it, yet you still try to come up to the surface with that. And for your information, everybody knows that SACD technology has been thrown out in the bath water a while ago. It was destined to be defunct, only a few companies tried to support it and it failed to impress the masses anyway. If you were not so ignorantly and reactionistly stubborn against the scientific facts, you would have read those thread links that I had given up there and seen the part where Mr Lavry says:

http://recforums.prosoundweb.com/index.php/mv/msg/2997/37350/0

We all based our opinions on what was available at that time and as the time moves on we all develop, experience and progress in what we know. That's how the science improves.

Let it go.

B.


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Steve Hill
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Re: One last technical point before the entire thread breaks down new [Re: Barish]
      #241084 - 22/01/06 11:42 PM
Since when SACD has died a death, and Sony have pledged $millions to compensate users who they arbitrarily chose to infect with embedded viruses!

192k is bound to have its defenders - lots of manufacturers have a massive vested interest in taking it up to the limit. The reality is I can't hear a difference.

I don't even bother to tell clients what I use (I can switch to quite a few things), I just ask if they like the sound. If they are happy at 44.1k, so am I. Far less strain on CPU and very respectable results for most (not all...) genres.

--------------------
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Barish
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Re: What is the point in 192kHz? new [Re: dubbmann]
      #241090 - 22/01/06 11:57 PM
Dubbmann thank you for understanding.

Regards,

B.


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__
Who's never been here


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Re: What is the point in 192kHz? new [Re: Barish]
      #241099 - 23/01/06 12:13 AM
Mate, Ive read a lot of your posts. How do you sleep at night being so f*cking perfect?


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default



Joined: 25/07/05
Posts: 1099
Re: What is the point in 192kHz? new [Re: The_BPP]
      #241100 - 23/01/06 12:13 AM
Nobody's mentioned that we still have to live with 24 Hz when we go watch a movie at the cinema. 24!!! This is outrageous !

Never mind kilo hetz - we are talking hertz here!

That's such a low resolution that it should have died before the stoneage ! It is not fair !

What are we complaining about? This needs to be rectified!

Immediately!



(PS - I really hope that was funny because it took me ages to get all those italics and bolds right - phew!)
ML


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Barish
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Re: What is the point in 192kHz? new [Re: __]
      #241105 - 23/01/06 12:21 AM
Quote ow:

Mate, Ive read a lot of your posts. How do you sleep at night being so f*cking perfect?




I am actually not. I am a perfectionist right enough, which is not a bad thing IMO, but I am not perfect. It's just that I only talk about things that I am sure I know right. Otherwise I shut up and read on (or listen up, or keep working). That's why you may think I know everything. There's always room for improvement for every one of us.


Oh, look, it's half twelve in the morning and I already feel sleepy. Nite nite





B.


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Re: What is the point in 192kHz? new [Re: Barish]
      #241106 - 23/01/06 12:22 AM
Nite Barish


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Stan



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Re: What is the point in 192kHz? new [Re: Barish]
      #241128 - 23/01/06 01:13 AM
Sweet dreams Barish, I'd just like to add , it does not take a bat or a dog to hear the difference sampling at 192kHz.
Dont knock it 'till you try it.
Long live science and long live art.

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sean1



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #241145 - 23/01/06 03:07 AM
I thought the reason why an analog system that could go to into 100k+ frequency response, sounds better is that they have the ability to critically track the wave form. This comes from there “high slew rates", not to be confused with the 20-20k audible range. So it also would to work with high sampling rates.
“Less digital fatigue”


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #241213 - 23/01/06 10:07 AM
I think it might be best just to retire to our respective corners on this one. No one is likely to be convinced of the counter arguments. Minds are closed and beliefs are two deeply held.

For the record, I'm of the opinion that 44.1 or 48kHz should be sufficient, but the practicalities of implementing a suitable design make it difficult to get right at budget prices. Pay big money for something at the real cutting edge, like a Prism converter, and you'll soon realise that there is nothing much wrong with 44.1 or 48kHz sampling.

For the rest of us, moving up to 96kHz is a very cost effective and practical workaround. Moving the cut-off point up another octave relaxes the constraints sufficiently that it becomes possible to get an excellent sound for the kind of budgets that are reasonable for hobbyists.

Moving it up again to 192kHz, in my opinion, can start to become counter-productive. Not just because of the data storage and processor overheads, but also because it starts to put a lot more strain on the design of some specific aspects of the converter. The result is that you have to go back to the top flight designers and pay a lot more more money to get something that works as intended.

But this is a very complex subject indeed, and there are a great many compromises and trade-offs involved -- most of which aren't obvious to the non-specialist.

If you happen to like the sound of manufacturer A's converter at 192kHz over manufacturer B's converter at 44.1, then great. It's a subjective choice and you are free to choose whatever works for your ears.

However, you cannot infer from that selection anything truly objective about the merits of 192 over 44.1, because there are far too many variables involved.

We all know how different analogue circuitry or circuit topologies can sound subtly (or even blatently) different. A lot of the sonic differences between otherwise similar converters is purely down to the design and layout of the analogue circuitry and the nature of the power supply system(s).

In the case above, Manufacturer A's converter would probably still sound different to manufacturer B's product at the same sample rate, simply becaue of the different analogue circuitry involved. We could then argue about which one was better -- the more technically accurate, or the one that sounded more 'analogue'... but we still wouldn't reach a concensus.

Objectivity doesn't get much easier even if you compare two converters from the same manufacturer, operating at different sample rates. Let's say unit A operating at 44.1 and unit B at 192. Same analogue electronics this time, but completely different decimation filters involved with different slopes, ripples and phase responses. The sonic differences here could easily be down to the choice of different decimation filters as to the sample rate itself.

In fact, some high end converter manufacturers actually incorporate four or five user-selectable filter characteristics, and switching between these without changing the sample rate at all produces distinct sonic differences easily as great as comparing two identical converters operating at different sample rates!

So come on, let's stop the pointless arguing. The theory is plain and incontrovertible. 44.1 should be enough, but practical construction constraints tends to let the theory down. 96kHz provides a reasonably convenient workaround. If done properly, 192 shouldn't be any worse, but doesn't really offer any advantages -- and if not done properly it can actually be less accurate than 96!

Of course, some people might like the less accurate version because it sounds 'more analogue'... and round we go again...

Oh, and film is shot with a sample rate of at 24 frames a second but the film projector oversamples the output by a factor of two or three times by using a rotating shutter.

Funny old world, isn't it!

hugh

--------------------
Technical Editor, Sound On Sound


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Magic Window



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #242124 - 24/01/06 04:47 PM
Digitising audio at 44100 samples a second means that, according to Nyquist's theorem, effectively record frequencies up to 22050 Hz. However, the higher the frequency, the less the detail - a 200 Hz sine wave will be far more accurately represented than a 13,000 Hz sine wave, and thus will sound much better.

For instance:

1Hz: 44100 / 1 = 44100 samples
30Hz: 44100 / 30 = 1470 samples
300Hz: 44100 / 300 = 147 samples
3000Hz: 44100 / 3000 = 14.7 samples
13000Hz: 44100 / 13000 = 3.39 samples

A 13000Hz sine recorded at 16-bit, 44100 Hz looks like this:



So, as you can see, high frequencies are not represented very well at 44100 Hz. Raising the bar to 96000 Hz, on the other hand, allows us, in the case of 13000 Hz, to have 7.38 samples per second, which is over double the accuracy of 44100:



We can see that the waveform is starting to approximate to a sine wave a lot clearly now. Not perfect, by any means, but this does show that even though a sampling rate of 44.1 Khz is adequate for representing frequencies over the human hearing threshold, high frequencies are represented horribly.


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Spord
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #242127 - 24/01/06 04:51 PM
No no no no no no no no no no no no I definitely won't get involved.

--------------------
Yes, good, very good, but everything LOUDER!


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Anonymous
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Re: What is the point in 192kHz? new [Re: Magic Window]
      #242147 - 24/01/06 05:15 PM
Magic Window, it isn't that simple. Any sinewave accurately may be reconstucted using only two samples.

Search the forum and main SOS site for some of the many posts and explanatory articles about how digital audio works. Or try getting hold of a copy of "The Art of Digital Audio" by John Watkinson (or pretty much any of his other books on the subject - they're all much the same) and find out about how the system works to produce an audio waveform from the stored data.


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UnderTow
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Re: What is the point in 192kHz? new [Re: Magic Window]
      #242164 - 24/01/06 05:34 PM
Quote Magic Window:



1Hz: 44100 / 1 = 44100 samples
30Hz: 44100 / 30 = 1470 samples
300Hz: 44100 / 300 = 147 samples
3000Hz: 44100 / 3000 = 14.7 samples
13000Hz: 44100 / 13000 = 3.39 samples






Rubbish. You only need 2 sample points for a sine wave.

Barish, there is an interesting discussion going on on the Pro Audio mailinglist about inter-sample peaks above 0 db FS. One comment has been made that increasing sample rates might help for avoiding inter-sample peaks that clip in the DCA.

Stan, you converters might sound better at 192Khz but that could just mean that your converters are broken at 44.1Khz... (without getting into how good humans are at convincing themselves of things that really don't exist). Things really are not as simple as they may seem.

UnderTow


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Barish
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #242183 - 24/01/06 05:57 PM
MagicWindow,

Do you know what "upsampling" and "downsampling" are and the concepts behind them?

Look, I have a life here. I am 35 and the time I have left for making music is getting less and less in my life. I have shown you the way to a specialist "designer/manufacturer" forum. Not a Pro audio power user forum. Go post your simple wireframe hangman diagrams there and see the technical roasting you are getting.

I can't get into an argument with people who approach to sampling concept with a four-operation calculator arithmetic. It won't get me anywhere.

That's as far as my contribution to this thread goes.


Ah, one last thing, for the chap who talks about generating square wave in synthesizer as part of the music:

In music, or any analog audio related concept for that matter, square wave means clipping. It is the menace that blows your tweeter, bursts your woofer, burns your amplifier's output stage and hurts your ears like a chinese torture. Why would you want to sample a squarewave in the first place? To convert it into a.... err... square wave?


Why don't you just connect the SPDIF output to your power amplifier and leave the converter alone?


That's all from me fellas.

B.


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hughb
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Re: What is the point in 192kHz? new [Re: Barish]
      #242241 - 24/01/06 07:29 PM
Nice to see the 'join the dots' misunderstanding rearing its ugly head again. How I have missed it.

--------------------
Tesco Value Tonmeister


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Ivories
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #242299 - 24/01/06 09:01 PM
To be fair to Magic Window, they weren't his dots, they were screen grabs from Audacity (Magic Window correct me if I'm wrong). Now that I've read Dan Lavry's article, I might invest in a more expensive audio editor

Thank you to the knowledgeable people who've shared their expertise in this thread; it's very educative for non-mathematicians like me. My one reservation about Dan Lavry's article was that I hope his maths is more accurate than his English. Confusing "whether" and "weather" might not make any difference to his argument, but if his summing graphs contain the same sort of elementary errors, then the overall picture might not be as he says it is.


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Barish
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Re: What is the point in 192kHz? new [Re: Ivories]
      #242356 - 24/01/06 10:21 PM
Quote Ivories:

Confusing "whether" and "weather" might not make any difference to his argument, but if his summing graphs contain the same sort of elementary errors, then the overall picture might not be as he says it is.




Well, with that spelling the man designed, made and sold some of the most appraised converters in the world today so he must know a bit or two about these things, don't you think?

Plus why would one want to piss in the reverse direction when everyone else has already jumped on the bandwagon in this 192kHz hype?

Let me quote Matthias Carstens of RME from an email (not directly to me, but to a distributor friend of mine who forwarded it to me), on Lavry's paper, before I go:

Quote Matthias Carstens:

"No surprise.

Nobody wants to hear the real truth. And if you tell someone the real truth, he won't believe you. I know this document, it's not new. The doc has been discussed all over the web. I think the basic information is correct.

Of course there is always a 'but if then'."





A food for thought.


Nite nite.

B.


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__
Who's never been here


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Re: What is the point in 192kHz? new [Re: Barish]
      #242382 - 24/01/06 10:43 PM
Barish, I owe you an apology for my rediculous 'perfect' outburst the other night. Dont know what came over me. I dont even know you man... i'm so sorry... sincerely... T


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Stan



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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #242448 - 25/01/06 12:41 AM
Hugh Robjohns, not for the first time, I really enjoyed your reply to this thread. It may be old hat to some but for me digital audio technology is fascinating and totally baffling at times. I love it.
Over the years I have noticed an SOS stand on 192kHz. I would call it diplomatic. It's why I trust you guys.
Salutations from a non-specialist.

--------------------
.. is this thing on?


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Brian Moynihan
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Re: What is the point in 192kHz? new [Re: ]
      #242456 - 25/01/06 01:01 AM
Quote 0VU:

Magic Window, it isn't that simple. Any sinewave accurately may be reconstucted using only two samples.




What about a non sine wave?



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Magic Window



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #242467 - 25/01/06 02:22 AM
Still makes no sense.

If you had two samples to represent a sine wave, surely the best you could do is a discontinous leap from one value to another? A square wave?


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UnderTow
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Re: What is the point in 192kHz? new [Re: Brian Moynihan]
      #242468 - 25/01/06 02:29 AM
Quote The Bob Campbell:

Quote 0VU:

Magic Window, it isn't that simple. Any sinewave accurately may be reconstucted using only two samples.




What about a non sine wave?





Every other wave can be described as a combination of sine waves. In other words, there are only sine waves.

UnderTow


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UnderTow
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Re: What is the point in 192kHz? new [Re: Magic Window]
      #242469 - 25/01/06 02:40 AM
Quote Magic Window:

Still makes no sense.

If you had two samples to represent a sine wave, surely the best you could do is a discontinous leap from one value to another? A square wave?




This is where people usually make the conceptual mistake: Digital audio isn't sound. It is an encoded signal _representing_ sound waves. To retrieve the encoded signal you need a decoder. In this case a Digital to Analogue Converter (DAC). Part of the decoder is a (lowpass) reconstruction filter that removes all the extra harmonics.

What happens when you filter out all the extra harmonics of a (theoretical) square wave? Yes, thats right: A perfect sine wave.

UnderTow


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Ivories
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Re: What is the point in 192kHz? new [Re: Barish]
      #242520 - 25/01/06 09:33 AM
Quote Barish:


Well, with that spelling the man designed, made and sold some of the most appraised converters in the world today so he must know a bit or two about these things, don't you think?
B.



I'm quite prepared to accept your opinion of his convertors (since they're way out of my price range, I can't try them for myself). However, since you asked for a scientific debate, I don't see how one person loving the sound of his 96 kHz convertor is any more admissible as evidence than another person loving another manufacturer's 192 kHz product. If Lavry's paper had been published in a peer-reviewed scientific journal, then non-scientists like me would probably be safe to assume that the technical content was beyond reproach; since he's simply published it on his own website, I think we're entitled to look at its obvious flaws and wonder whether they extend to the maths as well. That's why I like reading the arguments between you experts on the SOS forum, since you're more competent to judge that than I am .

Magic window, you seem to be in the same position mathematically as me, so I'll have a go at explaining the sine wave reconstruction bit: a DA convertor doesn't use straight lines join together the points on the graph made by the samples in the digitized waveform. The point of all the maths in the article Barish referred to was to prove what shape the lines ought to be. If you get the maths right, then the waveform will be reconstructed accurately, provided the sample rate is at least double the highest frequency present in the original waveform.


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Barish
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Re: What is the point in 192kHz? new [Re: Magic Window]
      #242699 - 25/01/06 02:37 PM
Quote Magic Window:

Still makes no sense.

If you had two samples to represent a sine wave, surely the best you could do is a discontinous leap from one value to another? A square wave?




Hint: Open the book called "Calculus and Analytic Geometry" and study the sections about Derivatives and Integrals.

That'll give you the basic idea how mathematical functions are derived into simpler forms via Derivation and then reconstructed back to their original states by Integration.

That's why I'm saying I can't waste time arguing with a logic that approaches to sampling concept with four basic mathematical operation (addition, subtraction, multiplication and division) mentality. You won't get anywhere with that logic. You can't design or explain an AD/DA converter with that level of mathematics either.

B.


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Brian Moynihan
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Re: What is the point in 192kHz? new [Re: UnderTow]
      #242714 - 25/01/06 02:56 PM
Quote UnderTow:

Quote The Bob Campbell:

Quote 0VU:

Magic Window, it isn't that simple. Any sinewave accurately may be reconstucted using only two samples.




What about a non sine wave?





Every other wave can be described as a combination of sine waves. In other words, there are only sine waves.

UnderTow




What happens when the wave you are describing with a combination of sine waves happens to be right at the upper limit of your sample rate? e.g. The theory shows that a 22.050khz sine wave can be correctly sampled and reproduced as long as the sampling rate is 44.1khz. If you take a theoretically perfect sine wave at either 1hz or 22.050khz normal sampling theory proves that a 44.1khz sampling system can reproduce it.

The difficulty I have with this is that waves are not perfect.

For example a soft bass guitar note may have a strong sine wave component (if we can effectively call it a sine wave) but it will contain many higher frequency harmonics and imperfections. A real world sine wave at 22.050 can also contain those higher harmonics and imperfections, which in reality would be components of frequencies higher that the 22.050. A bandpass filter in the converter will remove these minutae and therefore they are not passed to the sampling process.

For music's sake, this is not an issue, and the A-D is doing it's job correctly.

I would simply point out that it is not wholly accurate, you are employing a level of averaging to contain the information being fed to the digital process below a limit. If you wanted to be truly accurate, you would have to increase the sampling rate several times, even though you are effectively recording information that no-one can hear.

The question that should then be asked - is that extra information useless, or in a complex piece of music does it somehow add up to something that should be there?

Bob

p.s. if you think that information above the frequency range of human hearing does not need to be captured, think about this, if I take a 1khz sample, then combine it with another of equal volume but 1.01khz, I can create very audible "beats" that manifest themselves as a lower frequency. What if the two adjacent frequencies creating this lower frequency beat effect are not within the permitted frequency range, but lie outside it? Is a "human audible" sub-22050khz beat effect created by higher frequencies being lost when we filter out everything above 22050?


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Barish
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Re: What is the point in 192kHz? new [Re: Ivories]
      #242745 - 25/01/06 03:38 PM
Quote Ivories:

If Lavry's paper had been published in a peer-reviewed scientific journal, then non-scientists like me would probably be safe to assume that the technical content was beyond reproach; since he's simply published it on his own website, I think we're entitled to look at its obvious flaws and wonder whether they extend to the maths as well.




Only if you knew that in the forum the I directed you to, all his peers, including Herr Zeiss from Switzerland are debating on his paper for months.

I also remind you to read my quote from Herr Cartens of RME Audio about the paper. Of course, if you think he is a peer of Lavry's.


Too much argument with too little knowledge, that's what I see in this thread. That's why you are all running round in circles with "what if it's not sine wave and this wave, that wave."

You need to get basic sampling and mathematical concepts right first before getting into arguing the differences between waveforms. There are many sources where you can get information about these concepts and I don't want to look like Dan Lavry's champion here, but they are also available in Lavry's website in concise papers. Just read:

http://www.lavryengineering.com/documents/Sampling_Theory.pdf

http://www.lavryengineering.com/white_papers/sample.pdf

http://www.lavryengineering.com/white_papers/dnf.pdf

http://www.lavryengineering.com/white_papers/fir.pdf

http://www.lavryengineering.com/white_papers/iir.pdf

http://www.lavryengineering.com/white_papers/jitter.pdf


Cheers.

B.


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Magic Window



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Re: What is the point in 192kHz? new [Re: UnderTow]
      #242767 - 25/01/06 04:37 PM
Thanks for not being a hostile, bitter old bastard like our friend Barish over there. The calculus is irrelevant for one's understanding of how digital audio works on a basic level.

I understand it now, I think - samples are 'snapshots' of amplitude levels, but because speaker cones cannot move from one point to another instantaneously, you get a non-linear movement that "fills in" the sine wave even though there are only two sample points, right?


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James PerrettModerator



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Re: What is the point in 192kHz? new [Re: Barish]
      #242768 - 25/01/06 04:42 PM
Quote Barish:



Too much argument with too little knowledge, that's what I see in this thread. That's why you are all running round in circles with "what if it's not sine wave and this wave, that wave."






That's why it is always refreshing to receive messages from the pro-audio mailing list. At least you know that the discussions there are about things that will improve our understanding of audio rather than endless discussion of basic sampling theory.

Dan Lavry spent a fair bit of time discussing his ideas on the pro-audio list before giving them a wider public airing. Unfortunately it looks like the discussions are no longer in the list archives but, if you are really interested in the finer points of audio then take a look at http://www.pgm.com/mailman/listinfo/proaudio

Cheers

James.

--------------------
JRP Music - Audio Mastering and Restoration.
http://www.jrpmusic.net


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hughb
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Re: What is the point in 192kHz? new [Re: Magic Window]
      #242789 - 25/01/06 05:10 PM
Quote Ivories:

To be fair to Magic Window, they weren't his dots, they were screen grabs from Audacity (Magic Window correct me if I'm wrong). Now that I've read Dan Lavry's article, I might invest in a more expensive audio editor




That's what I mean about the misunderstanding - these screen grabs seem to give a very misleading message, since they neither show a stream of samples (as quantised steps) or a reconstructed waveform. I wasn't implying that MagicWindow had drawn himself some dots and joined them together!

Quote Magic Window:


I understand it now, I think - samples are 'snapshots' of amplitude levels, but because speaker cones cannot move from one point to another instantaneously, you get a non-linear movement that "fills in" the sine wave even though there are only two sample points, right?




Not quite - you're right about the samples being snapshots, but the reconstruction of the waveform from the samples happens within the DAC, way before it gets to any speakers. In a reconstruction filter, in fact. It really does require some nasty maths to describe it properly, I'm afraid.


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UnderTow
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Re: What is the point in 192kHz? new [Re: UnderTow]
      #242834 - 25/01/06 06:06 PM
Quote UnderTow:



Every other wave can be described as a combination of sine waves. In other words, there are only sine waves.





AHA! I've been doing some reading since this post and apparantly the above statement I made is incorrect! (or incomplete).

Here is a quote from Dan Lavry on the Prosoundweb forum:
Quote:


...music is not all sine waves, and music can not be "taken apart" to sine waves.

Fourier found that any PERIODIC wave (endless repetitive identical cycles) can be "broken down" into "basic elements" - sine and cosine wave, all at frequencies that relate to the basic pitch by somle integers.

But much of music is not made of PERIODIC waves. The attack, the decay of a note (and much more) are NON PERIODIC. The "near periodic" part of a note is that duration after trhe attack and before the decay, where some instruments (like a pipe organ) "stays steady for a while. That "steady portion" can be looked at as "almost Fourier like.

But as a rule, music is not the sum of sine waves.

Yet Sine waves are great tools for testing part of the system behaviour (not all).

And while at it, if one wishes to "break" a signal up into "basic elements", it can be done as follows:

A. Define a proper impulse response wave:
Take the maximum signal bandwidth. That bandwidth corresponds to some impulse response (the more bandwidth the narrower the impulse). The shape of the impulse is the sinc function (sine X/X).

B. sampling:
Now sample the signal at a rate slightly greater then twice the bandwidth.

C. At each sample time, insert the impulse wave (see A. above), and make the each inserted impulse amplitude equal to the corresponding sample value.

D. Add all the impulses from C. That is it! the "elements" (properly scaled impulse waves placed at all sample times) will add up to your original wave (which can be an hour of Beethoven symphony, or the sound of the wind or whatever... within the agreed original bandwidth.





Sorry for confusing things.

PS: Anyway, Barish didn't comment on this so either he isn't paying attention or his knowledge isn't as complete as he is claiming.

PPS: It is a bad teacher that blames his students for not understanding the lesson ... I'm sure you can figure what this comment is directed at.

UnderTow

Edited by UnderTow (25/01/06 06:10 PM)


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Brian Moynihan
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #242864 - 25/01/06 07:07 PM
I'd forgotten why I quit posting, now it's come back to me, people have a habit of not reading (or responding to) what is typed....

Bob


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Barish
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Re: What is the point in 192kHz? new [Re: Brian Moynihan]
      #242869 - 25/01/06 07:17 PM
Yes, that's my mistake. I should have let this thread go after my first post.

Other folks, call me any name you want. It's not my money you'll be spending after all. Why should I care.

Get what makes you happy.


B.


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Lighthouse_Mastering



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Re: What is the point in 192kHz? new [Re: Barish]
      #242889 - 25/01/06 07:52 PM
Quote Barish:

Yes, that's my mistake. I should have let this thread go after my first post.

Other folks, call me any name you want. It's not my money you'll be spending after all. Why should I care.

Get what makes you happy.


B.




I have been tempted to post on this thread about half a dozen times, but I have resisted. I don't want to get into arguements or putting people down.

Lets face it, the highest quality medium (widely) available to the consumer is 44.1khz 16bit CD. With the loudness war, the quality of most commercial material is awful, and most people are now listening to low res MP3. I always advise people to work with 44.1, using the highest quality equipment they can afford. There is no substitute for good Mikes, Preamps, and ADC's. Also a good set of monitors, and avoiding the over use of cheap digital plugins.

The quality of your equipment, and especially your ability to use it are going to have a far bigger impact than the sample rate.

Dave

--------------------
Lighthouse Mastering


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Steve Hill
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Re: What is the point in 192kHz? new [Re: Magic Window]
      #242925 - 25/01/06 08:42 PM
Quote Magic Window:

Thanks for not being a hostile, bitter old bastard like our friend Barish over there.




I think Barish has more knowledge in his little finger than you, my friend, are likely to acquire in several lifetimes based on the slender evidence of your very few posts on this forum to date.

However, if you wish to continue to make a complete prat of yourself, go ahead. I'm sure you will be indulged. For a while.

--------------------
Dynamite with a laser beam...


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Studio Support Gnome
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Re: What is the point in 192kHz? new [Re: Barish]
      #242927 - 25/01/06 08:45 PM
Quote:

What is the point in 192kHz?





it's the decimal . tells you it's 192000.00 Hz. Not 192.00000 Hz or 1920.0000 or 19200.000 Hz

.




I don't consider there to be any real world advantage in actually working at 192KHz.

HOWEVER

I DO consider there to be an advantage in the 192KHz capable converters and so on....



Bluntly, the Digidesign 192 interface is the best sounding AD/DA thing they have EVER made....

EVEN WHEN WORKING AT 44.1KHz

and the same applies to the MOTU 192HD

( and their 896HD)


The same applies to the Apogee Rosettas, Lavry, DCS, Benchmark and a whole heap of other stuff ..

all these PROPER High Rate capable high end converters also sound better than their predecessors did.... even when working at more mundane and sensible sample rates.,

IMHO there is a worthwhile improvement to be had out of 96KHz sample rate for serious work, but 192 as a working rate is not only pointless , but self defeating... But in general 44.1/48 KHz is largely sufficient.

My (educated) guess is that the knock on benefit of the manufacturers tooling up to work at these elevated rates, is that we get better clocks and converters to continue working at the rates we feel most comfortable with in the balance between ultimate fidelity and practical usefulness.

--------------------
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__
Who's never been here


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Re: What is the point in 192kHz? new [Re: The_BPP]
      #242951 - 25/01/06 09:28 PM
I'm intrigued by all this. So ive tuned to 192Khz long wave of course. And ive got a very interesting French phone in show. Dont know what theyre saying but if I hang around theres bound to be a woman phone in and they always sound like they are talking about shagging to me.


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Stevedog



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #242955 - 25/01/06 09:35 PM
From a slightly sideways non technical view... I could never get on with the film *Full metal jacket* and it's for a seemingly strange reason, and maybe even a totally superfulous one.

The clothing is accurate, the hardware is accurate, the language is spot on. But the light is all wrong. The sky over the London Docklands can never look like Vietnam becasue its way too North too. The colour is different even when it is cloudy.


Now i didn't know that that was where it was shot when i saw it first ,but said after, the light was wrong, sorry it ruined it for me. Now i accept that the vast majority of people probably 1... didn't even notice and 2.. couldnt give a flying duck anyway. However, i did it just made the whole experience totally phoney for me.

To go to all that effort to be convincing and then throw the baby out with the bathwater with the sky seemed to me to be way more stupid than just playing totally fast and loose with the whole continuity. He could have made just as good a movie with the same message using a wholly fictitious setting and war.

Now the relevance to 192 is this... if you haven't fallen asleep already.... 192 offers all the proper continuity and the right location, where location is the recorded acoustic in full, whereas lower sampling rates are the equivalent of a studio recreaton of the location.

Yes, to most people it will not worry or bother them , even if they notice at all, but there will always be that small section of the public who demand more.

It is up to the artist and the project manager to decide whether they want to indulge in total continuity and do so in the full knowledge that it will mostly go over peoples heads.

Be that as it may, maybe, just maybe, musical recordings that have true longevity will more often come from the school of total continuity because even if it is only subconciousm, people have an intrinsic sense of when they are listening or watching the *real thing* as opposed to a studio recreation.

--------------------
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Richard Steed
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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #242973 - 25/01/06 10:09 PM
Quote Hugh Robjohns:

I think it might be best just to retire to our respective corners on this one. No one is likely to be convinced of the counter arguments. Minds are closed and beliefs are two deeply held.

For the record, I'm of the opinion that 44.1 or 48kHz should be sufficient, but the practicalities of implementing a suitable design make it difficult to get right at budget prices. Pay big money for something at the real cutting edge, like a Prism converter, and you'll soon realise that there is nothing much wrong with 44.1 or 48kHz sampling.

For the rest of us, moving up to 96kHz is a very cost effective and practical workaround. Moving the cut-off point up another octave relaxes the constraints sufficiently that it becomes possible to get an excellent sound for the kind of budgets that are reasonable for hobbyists.

Moving it up again to 192kHz, in my opinion, can start to become counter-productive. Not just because of the data storage and processor overheads, but also because it starts to put a lot more strain on the design of some specific aspects of the converter. The result is that you have to go back to the top flight designers and pay a lot more more money to get something that works as intended.

But this is a very complex subject indeed, and there are a great many compromises and trade-offs involved -- most of which aren't obvious to the non-specialist.

If you happen to like the sound of manufacturer A's converter at 192kHz over manufacturer B's converter at 44.1, then great. It's a subjective choice and you are free to choose whatever works for your ears.

However, you cannot infer from that selection anything truly objective about the merits of 192 over 44.1, because there are far too many variables involved.

We all know how different analogue circuitry or circuit topologies can sound subtly (or even blatently) different. A lot of the sonic differences between otherwise similar converters is purely down to the design and layout of the analogue circuitry and the nature of the power supply system(s).

In the case above, Manufacturer A's converter would probably still sound different to manufacturer B's product at the same sample rate, simply becaue of the different analogue circuitry involved. We could then argue about which one was better -- the more technically accurate, or the one that sounded more 'analogue'... but we still wouldn't reach a concensus.

Objectivity doesn't get much easier even if you compare two converters from the same manufacturer, operating at different sample rates. Let's say unit A operating at 44.1 and unit B at 192. Same analogue electronics this time, but completely different decimation filters involved with different slopes, ripples and phase responses. The sonic differences here could easily be down to the choice of different decimation filters as to the sample rate itself.

In fact, some high end converter manufacturers actually incorporate four or five user-selectable filter characteristics, and switching between these without changing the sample rate at all produces distinct sonic differences easily as great as comparing two identical converters operating at different sample rates!

So come on, let's stop the pointless arguing. The theory is plain and incontrovertible. 44.1 should be enough, but practical construction constraints tends to let the theory down. 96kHz provides a reasonably convenient workaround. If done properly, 192 shouldn't be any worse, but doesn't really offer any advantages -- and if not done properly it can actually be less accurate than 96!

Of course, some people might like the less accurate version because it sounds 'more analogue'... and round we go again...

Oh, and film is shot with a sample rate of at 24 frames a second but the film projector oversamples the output by a factor of two or three times by using a rotating shutter.

Funny old world, isn't it!

hugh



So id say that basically different sample rates dont really play a significant role in the quality of the production when the quality of it is really determined by the use of different use of decimation filters.
I really think we shouldnt worry about different sample rates at all.We should all be thinking about the different use of filters and equalizers which both determine the main quality of production.
Richie Steed.
www.soundclick.com/steedie

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RSteed


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Juju Money
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Re: What is the point in 192kHz? new [Re: Richard Steed]
      #243055 - 26/01/06 12:23 AM
Of all the gin joints complex threads, in all the towns forums, in all the world, she had to walk into mine this one...

Well I'm sure "we" will all sleep better now that Richie Steed has cut the chaff out of the argument and revealed its beating heart for all lesser mortals to see clearly. Unless of course that was the 'Royal "we"', in which case I think "we" should leave well alone and get back to the colouring books...

Barish, Mr Robjohns et al, you have my sympathies.....

J/


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Magic Window]
      #243687 - 27/01/06 11:33 AM
Quote Magic Window:

Digitising audio at 44100 samples a second means that, according to Nyquist's theorem, effectively record frequencies up to 22050 Hz. However, the higher the frequency, the less the detail - a 200 Hz sine wave will be far more accurately represented than a 13,000 Hz sine wave, and thus will sound much better.




This is a common argumant, but is technically incorrect I'm afraid. If you re-assess the Nyquist theorem you quote, you'll see that the signal can be fully reconstructed -- without any waveshape distortion and with perfect accuracy -- provided there are at least two samples per cycle. The maths proves this without any doubt whatever.

Quote:

We can see that the waveform is starting to approximate to a sine wave a lot clearly now.




Again, a common mis-interpretation of the graphics. Your waveform has not been processed correctly. This is a very crude join-the-dots represenation of the D-A process. The essential 'recontruction filtering' element of the D-A process has not been performed here. The reason for the apparently poor waveshape reconstruction is because the signal as shown is still full of image frequencies. Pas the same data through an appropriate reconstrcution filter to remove those images, and the pure sinewave signal will be recovered in all its pristine glory.

Quote:

Not perfect, by any means, but this does show that even though a sampling rate of 44.1 Khz is adequate for representing frequencies over the human hearing threshold, high frequencies are represented horribly.




As explained, it shows no such thing!

hugh

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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Brian Moynihan]
      #243710 - 27/01/06 12:05 PM
Quote The Bob Campbell:

What if the two adjacent frequencies creating this lower frequency beat effect are not within the permitted frequency range, but lie outside it? Is a "human audible" sub-22050khz beat effect created by higher frequencies being lost when we filter out everything above 22050?




This could indeed be an issue, but only in some very specific circumstances. Consider the case of an orchestra -- strings and brass are known to generate a fairly significant ultrasonic spectrum. These ultrasonic elements will produce beats as the sound from the various instrumetns mixes in the air before reaching the (stereo) mic. Hence the mics will capture the audible beats and they will be recorded int a digital system in exactly the same way as in an analogue recording system.

The same will be true of multiple live sources mixed through an analogue console before recording digitally. Good analogue circuitry has a very wide bandwidth, and ultrasonic signals will be able to interact and produce audible beats within the analogue circuits.

The potential fly in the ointment comes when recording tracks individually, and when overdubbing. In these cases, ultrasonic signals are removed as the source is recorded, and hence they can not interact with those of other signals during the mixing stage.

Perhaps these thoughts go some way to explaining why multitracked digital projects seem to lose some of the 'warmth' we associated with analogue, whereas straight-to-stereo projects seem to benefit from digital.

hugh

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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Magic Window]
      #243714 - 27/01/06 12:21 PM
Quote Magic Window:

Thanks for not being a hostile, bitter old bastard like our friend Barish over there.




In fact, of course, he is none of those things. He is knowledgeable, accurate, right and patient beyond all reason!

Quote:

The calculus is irrelevant for one's understanding of how digital audio works on a basic level.




Maybe, but so far there appears to be a lack of even a rudimentary understanding of the basics from your corner, and a refusal to accept the generous help offered by those who clearly do understand the subject well.

Quote:

I understand it now, I think - samples are 'snapshots' of amplitude levels




Yes, they are, but they cannot be contemplated as individual events. They are utterly meaningless as individual samples -- the audio signal is not conveyed by individual samples but by the ongoing stream. One sample by itself is just a click. You cannot determine the fundamental frequency of a signal by looking at a single sample -- or even a pair.

So clearly, your 'understanding' that a sample is a snapshot of signal amplitude is very limited in its ability to help explain the principles of digital audio.

Quote:

... but because speaker cones cannot move from one point to another instantaneously, you get a non-linear movement that "fills in" the sine wave even though there are only two sample points, right?




Wrong. The 'filling in' as you call it is done by the reconstruction filtering stage of the D-A conversion.

hugh

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Barish
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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #243730 - 27/01/06 01:02 PM
Quote Hugh Robjohns:

Quote Magic Window:

Thanks for not being a hostile, bitter old bastard like our friend Barish over there.




In fact, of course, he is none of those things. He is knowledgeable, accurate, right and patient beyond all reason!

MagicWindow Quote:

The calculus is irrelevant for one's understanding of how digital audio works on a basic level.




Maybe, but so far there appears to be a lack of even a rudimentary understanding of the basics from your corner, and a refusal to accept the generous help offered by those who clearly do understand the subject well.






Hugh,

I am humbled.

Among all that commotion I didn't have a chance to make a point about Dan Lavry's negative comments about your integrity/sincerity in your articles in his post there. I personally don't agree with his views on that, which is why I am here participating. We all base our views on what is available to us in any given time and as the time passes we all find out that sometimes the things we thought to be right were actually wrong and the ones we thought to be wrong were in fact, right. I hope Dan Lavry has a chance to see that in your articles, AND in his comments as well.

Quote MagicWindow:

The calculus is irrelevant for one's understanding of how digital audio works on a basic level.




That's correct. But your problem is, the area that you are trying to understand/explain is not the basic level of how digital audio works. It is quite an advanced part of it.

That's why no matter how many times people tell you about reconstruction filters it keeps going over your head.

If you don't know the concepts of derivation and integration, there is no way you can fully picture the processes of AD and DA respectively in your mind.


Open up the Calculus and analytic geometry book and look at the graphical representations of the mathematical functions and their similarity to the graphic representation of sound waves.


Sound is mathematic.


It can be mathematically represented in a function.


Functions can be derived (which is what Analog-to-Digital conversion is all about).

Derivatives can be intregrated (which is what Digital-to-Analog conversion is all about).


If four basic operations is all you know about mathematics, then you have no other choice but to connect two dots with a straight line. But as soon as it turns into a curve, you need a higher mathematics. If it turns into a spline, it requires even higher mathematics.

That's why people keep missing the point when reconstruction filter is mentioned.

It is a very complex issue and there are some facts that straight logic falls short to explain. You certainly need a certain amount of higher mathematic knowledge in order to debate on the fidelity issues in AD/DA process.

B.


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yorkio
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Re: What is the point in 192kHz? new [Re: Stevedog]
      #243773 - 27/01/06 02:43 PM
Quote Stevedog:

From a slightly sideways non technical view... I could never get on with the film *Full metal jacket* and it's for a seemingly strange reason, and maybe even a totally superfulous one.

The clothing is accurate, the hardware is accurate, the language is spot on. But the light is all wrong. The sky over the London Docklands can never look like Vietnam becasue its way too North too. The colour is different even when it is cloudy.




I had a bigger problem with the Beckton Alp dry ski slope which loomed up in the background from time to time! Charlie don't ski!


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Magic Window



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #244611 - 29/01/06 02:24 PM
Barish,

My apologies, sir. My rude comments earlier were a kneejerk reaction to some pretty bad news. You know how humans are very bad with dealing with bombshells. I am grateful for you and Hugh and everyone to explain to me what is really going on.

No hard feelings, please?

If I may continue, I would like to know how more complex signals are treated. Am I right in maintaining that the reconstruction filter does the same for say, white noise, as it does for a sine wave? A friend of mine suggested that the characteristics of the filter may 'colour' it a certain way, and this is why you've been talking about using one's ears and personal taste to determine if an audio system is to your taste?


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smiling stranger
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #244692 - 29/01/06 06:30 PM
I love debates like this (except people usually ignore me, nevermind..)

I fully appreciate that for some sound sources a higher frequency sampling rate is preferable.

Surely though, if the music is going to end up on CD at 44,100Hz then recording at whole number multiplications of 44.1KHz is preferable thereby leaving headroom in the system but more importantly eliminating (?) any aliasing and other artefacts of sample rate conversion in the mastering stage.

Someone please acknowledge this and tell me if I'm right or wrong; it's like talking at a brick wall (limiter) in here sometimes....


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: smiling stranger]
      #244751 - 29/01/06 08:31 PM
Quote smiling stranger:

Surely though, if the music is going to end up on CD at 44,100Hz then recording at whole number multiplications of 44.1KHz is preferable thereby leaving headroom in the system but more importantly eliminating (?) any aliasing and other artefacts of sample rate conversion in the mastering stage.




The sampling rate has no effect on the headroom. That is determined entirely by how much headroom you choose to leave when recording/post-producing. Furthermore, the sampling rate has no effect on aliasing artefacts when sample-rate converting: that is down to the accuracy of the maths involved in creating the appropriate reconstruction filtering.

With early sample rate converters, the limited (by modern standards) accuracy of the process meant that there were often sonic advantages to using simple multiples of sample rates -- 88.2 for conversion to 44.1 rather than 96, say. However, these days, modern SRCs are stunningly accurate -- far more so than most converters in fact, regardless of the input/output rate ratios.

As proof of this, the superb Benchmark DAC 1 -- one of the best sounding D-As available -- passes everything through a sample rate converter which outputs at roughly 110kHz regardless of the input rate. Everyone complements the DAC1 on its sound quality and no one is the least worried about the non-interger sample rate conversion!

hugh

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Eduardo



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #244930 - 30/01/06 10:10 AM
I think we need to remember a simple fact about digitising analogue waveforms:

It is widely accepted that to capture a waveform with some accuracy, the sample rate must be at least twice that of the highest frequency to be recorded. 44.1kHz would appear to be adequate for audio signals up to 22.5kHz for example.

However, a significant problem at 22.5kHz is that a pure sine wave would appear slightly 'triangulated' if digitised literally. This is because there are a maximum of two samples at that frequency, and the line that joins them is not a curve but a straight line. This is, perhaps, why high frequencies sound harsher on digital recordings at 44.1kHz.

Although there are software algorithms to correct this flaw, few can claim to know what exactly occurs between the sample 'points' and so can only give an approximation as it might be more complex than a sine wave.

Clearly, a higher sampling rate improves the digitisation at high frequencies (including those within the hearing range). This assumes that the AD conversion is of decent quality and not compromised by the extra speed.

Some argue that it will be mixed down to 44.1kHz anyway (for CD) and that you would require, say, a 96kHz player to appreciate the difference. However, if the mixing of various waveforms is done at a higher sampling resolution than 44.1, the resultant waveform will reproduce the interplay of harmonics better, and the final master will include most of these subtleties.


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Feefer
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Re: What is the point in 192kHz? new [Re: Stevedog]
      #244951 - 30/01/06 10:31 AM
Quote Stevedog:

Now the relevance to 192 is this... if you haven't fallen asleep already.... 192 offers all the proper continuity and the right location, where location is the recorded acoustic in full, whereas lower sampling rates are the equivalent of a studio recreaton of the location.





I had a chance to talk to a very successful sound engineer @ NAMM about recording at higher sampling rates (96kHz / 192kHz), and he felt that even though we're outside the range of frequencies that are audible to human ears, there IS a slight improvement in terms of the sense of space, imaging, and localization of the instruments in the recording. Recordings with higher sampling rates, when listening under ideal conditions, seem better for capturing the reverberation characteristics, or the "air", of the room the recording was made.

As mentioned, there's greater hassles in dealing with larger amounts of data, and the approach is not beneficial for all types of recording (more applicable to minimalistic classical music recordings or 5.1 surround, but not to closed-miced multi-track rock studio stuff).

As stated, this is a situation of diminishing returns: while some listeners MAY able to appreciate a difference, for the clear majority of listeners (using consumer-grade audio equipment) the difference is imperceptible.

Don't flame me: that's what this egg-headed recording engineer told me....

(And after someone guffaws, I'll share how many Grammys he has won for best-engineered classical music recording...)

Chris

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Anonymous
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Re: What is the point in 192kHz? new [Re: Eduardo]
      #244958 - 30/01/06 10:51 AM
Quote:

Eduardo:
I think we need to remember a simple fact about digitising analogue waveforms:

It is widely accepted that to capture a waveform with some accuracy, the sample rate must be at least twice that of the highest frequency to be recorded. 44.1kHz would appear to be adequate for audio signals up to 22.5kHz for example.

However, a significant problem at 22.5kHz is that a pure sine wave would appear slightly 'triangulated' if digitised literally. This is because there are a maximum of two samples at that frequency, and the line that joins them is not a curve but a straight line. This is, perhaps, why high frequencies sound harsher on digital recordings at 44.1kHz........ *snip*

.....done at a higher sampling resolution than 44.1, the resultant waveform will reproduce the interplay of harmonics better, and the final master will include most of these subtleties.





Here we go again!

You clearly either didn't read or didn't understand the rest of this thread! Before you start reminding people of simple facts can I suggest you do read it and try to understand it because you seem to be missing a few simple facts that we've been over..and over...and over....


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The Byre



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #244964 - 30/01/06 11:07 AM
Gegen die Dummheit kaempfen die Goetter selbst vergebens.

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Barish
Kebab Mafia


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Re: What is the point in 192kHz? new [Re: Eduardo]
      #244998 - 30/01/06 12:14 PM
Quote Eduardo:

I think we need to remember a simple fact about digitising analogue waveforms:

It is widely accepted that to capture a waveform with some accuracy, the sample rate must be at least twice that of the highest frequency to be recorded. 44.1kHz would appear to be adequate for audio signals up to 22.5kHz for example.

However, a significant problem at 22.5kHz is that a pure sine wave would appear slightly 'triangulated' if digitised literally. This is because there are a maximum of two samples at that frequency, and the line that joins them is not a curve but a straight line. This is, perhaps, why high frequencies sound harsher on digital recordings at 44.1kHz.

Although there are software algorithms to correct this flaw, few can claim to know what exactly occurs between the sample 'points' and so can only give an approximation as it might be more complex than a sine wave.

Clearly, a higher sampling rate improves the digitisation at high frequencies (including those within the hearing range). This assumes that the AD conversion is of decent quality and not compromised by the extra speed.

Some argue that it will be mixed down to 44.1kHz anyway (for CD) and that you would require, say, a 96kHz player to appreciate the difference. However, if the mixing of various waveforms is done at a higher sampling resolution than 44.1, the resultant waveform will reproduce the interplay of harmonics better, and the final master will include most of these subtleties.




Lord Almighty please give me patience...


Please read, dude. PLEASE.


Do everyone here a favour. Please READ the thread all throughout before posting.


I have spent days here trying to explain why the opinions like yours are wrong, with the simplest technical and mathematical language possible so that the simple fellas with four-operation maths like you can understand.


What's more dangerous than being ignorant about something is to be unaware of how ignorant oneself actually is.


Please don't be that.


Look what I'd written a few posts above yours:

Quote Barish:

If you don't know the concepts of derivation and integration, there is no way you can fully picture the processes of AD and DA respectively in your mind.


Open up the Calculus and analytic geometry book and look at the graphical representations of the mathematical functions and their similarity to the graphic representation of sound waves.


Sound is mathematic.


It can be mathematically represented in a function.


Functions can be derived (which is what Analog-to-Digital conversion is all about).

Derivatives can be intregrated (which is what Digital-to-Analog conversion is all about).


If four basic operations is all you know about mathematics, then you have no other choice but to connect two dots with a straight line. But as soon as it turns into a curve, you need a higher mathematics. If it turns into a spline, it requires even higher mathematics.

That's why people keep missing the point when reconstruction filter is mentioned.

It is a very complex issue and there are some facts that straight logic falls short to explain. You certainly need a certain amount of higher mathematic knowledge in order to debate on the fidelity issues in AD/DA process.







B.


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Stoney



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #245103 - 30/01/06 02:44 PM
I must admit, I am rather astonished by how little people know and yet they claim to know what they're talking about.

Now, I certainly don't claim to know what I'm talking about with any authority, but the things I think I have picked up over the last few years are these:

1. You only need 2 points I.e. 2 samples of amplitudes, to create a sine wave at the reconstruction filter I.e. it joins the dots with a smooth curve - not a straight line.

2. The maximum frequency you can hear (or just over) is ALL the information you need (ignoring "beat" effects etc). Therefore any extra information that would be between the two points sampled is excess info and can be lost. I.e. the highest frequency sine wave you recreate is literally the highest frequency you need and hence all other *detail* can be discarded.. This gives you the sample rate for 22.5kHz:
22.5kHzx2(samples)=44.1kHz

3. A visual description might help: The wave form you would see in a wave editor can be thought of as a combination of many frequencies of sine waves occurring at different times and amplitudes, but adding together to form one continuous line or one wave. If you magnified an actual soundwave at a point and looked closely, you would see detail that is smaller in wavelength than a 22.5kHz wave BUT as you can't hear this detail you don't need it when digitising.

I've tried to make some sense of this in my own head and I'm hoping I've pretty much got there - and therefore my simplified explanation should be able to help others...... However, If I'm wrong, please feel free to shoot me down.

D


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Brian Moynihan
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #245159 - 30/01/06 04:32 PM
http://jn.physiology.org/cgi/content/full/83/6/3548


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Marky
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Re: What is the point in 192kHz? new [Re: Brian Moynihan]
      #245182 - 30/01/06 05:01 PM
The industry's focus on the 192kHz issue is pretty ironic. It seems more concerned over trying to catch supersonic sounds (which tape could capture anyway) than it does in dealing with the real issues clouding sound fidelity these days ... namely a) the dominance of sub-standard audio codecs like MP3 and WMA and b) the so-called "loudness wars" which have resulted in most popular music today sounding harsh and brittle at any level of volume, and being mostly void of any dynamics.

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James PerrettModerator



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Re: What is the point in 192kHz? new [Re: Brian Moynihan]
      #245184 - 30/01/06 05:03 PM
Quote The Bob Campbell:

http://jn.physiology.org/cgi/content/full/83/6/3548




That's the Oohashi paper that I mentioned in an earlier post. No-one has been able to repeat the findings as far as I know. Unfortunately I can't find any of the postings that refute his claims or question the methodology but I believe that people have tried to repeat the experiments and haven't seen the same results.

Cheers

James.

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Barish
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Re: What is the point in 192kHz? new [Re: Brian Moynihan]
      #245198 - 30/01/06 05:17 PM
Quote The Bob Campbell:

http://jn.physiology.org/cgi/content/full/83/6/3548




I need to check if this experiment is a different one than the Japanese study that was later on discredited as it failed to replicate the results at a later attempt.

B.


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Barish
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Re: What is the point in 192kHz? new [Re: James Perrett]
      #245201 - 30/01/06 05:19 PM
Quote James Perrett:

Quote The Bob Campbell:

http://jn.physiology.org/cgi/content/full/83/6/3548




That's the Oohashi paper that I mentioned in an earlier post. No-one has been able to repeat the findings as far as I know. Unfortunately I can't find any of the postings that refute his claims or question the methodology but I believe that people have tried to repeat the experiments and haven't seen the same results.

Cheers

James.




There you go.

B.


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Eduardo]
      #245208 - 30/01/06 05:30 PM
Quote Eduardo:

However, a significant problem at 22.5kHz is that a pure sine wave would appear slightly 'triangulated' if digitised literally. This is because there are a maximum of two samples at that frequency, and the line that joins them is not a curve but a straight line. This is, perhaps, why high frequencies sound harsher on digital recordings at 44.1kHz.




Aaarrgggghhhhh! have you read nothing of the preceeding three pages?

Quote:

Although there are software algorithms to correct this flaw, few can claim to know what exactly occurs between the sample 'points' and so can only give an approximation as it might be more complex than a sine wave.




I don't have the mental strength to answer this in depth. Suffice to say that, by definition in the Sampling theorum, the anti-alias filter removes everything above half the sample rate. Therefore a 22.05kHz signal -- even assuming that was allowed through in itself, which of course it can't be in a practical 44.1 kHz system -- can be nothing other than a sine wave, since it would not be allowed to contain any harmonics whatever!

Quote:

Clearly, a higher sampling rate improves the digitisation at high frequencies




No. In theory it just allows a wider bandwidth to be encoded. In practice, there are often some audible benefits because of the slightly relaxed requiements on the anti-alias and reconstruction filtering, amongst other issues.

Quote:

However, if the mixing of various waveforms is done at a higher sampling resolution than 44.1, the resultant waveform will reproduce the interplay of harmonics better, and the final master will include most of these subtleties.




True enough -- although how significant that aspect is remains to be formally proved.

hugh

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Dishpan



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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #245217 - 30/01/06 05:40 PM
> This is a common argumant, but is technically incorrect I'm afraid. If you re-assess the Nyquist theorem you quote, you'll see that the signal can be fully reconstructed -- without any waveshape distortion and with perfect accuracy -- provided there are at least two samples per cycle. The maths proves this without any doubt whatever.

Not strictly applicable in a digital system with limited bit-depth. The theorem only works provided there are at least two samples of INFINITE PRECISION per cycle. It's a subtle, but important distinction which never seems to be mentioned.

In a digital system we don't have infinite precision, therefore higher sample rates can increase the accuracy of <1/2 sample rate frequencies (especially lower level ones). Whether we can actually hear this (and we probably can't) is another matter entirely of course.


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Michael Harrison
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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #245410 - 31/01/06 12:56 AM
Quote arish:

Lord Almighty please give me patience...




Quote Hugh Robjohns:

Aaarrgggghhhhh! have you read nothing of the preceeding three pages?




I'm laughing... and wincing simultaneously!

Full marks & extra merit points for patience, Hugh & Barish.

Quote Eduardo:

few can claim to know what exactly occurs between the sample 'points'




Actually... not true. Anything (of greater detail than the sine wave described) between two sample points is, by nature, greater than 22.05kHz. If you're talking about reconstructing frequencies above this point then no, a 44.1kHz system won't do this. However, as we're talking about the ability of the system to accurately reproduce frequency content below the Nyquist frequency, then this information -by definition - is irrelevant to the argument/explanation in hand.

Quote:

...and so can only give an approximation as it might be more complex than a sine wave.




As explained above... there is no approximation. Prequencies below Nyquist are reproduced accurately. Frequencies above Nyquist are not reproduced.

I'm far from an authority on the matter, but my understanding (I hope) of digital audio has improved significantly over the last few years, thanks to the postings of people (not least Hugh ) here.

Regards,

Mike

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DCompton



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #245418 - 31/01/06 01:18 AM
If you apply the nyquist theoreom to a 44.1kHz sample rate the highest fundamental frequency that can be produced by a complex wave is ~11kHz - remembering that the harmonics of a complex wave will extend further into the high frequency region at multiple integers of the fundamental.

fundamental 11kHz
1st Harmonic 22kHz
2nd Harmonic 33kHz

at a 44.1kHz sample rate the low pass filter in the ADC will cut off all the upper harmonics at 22.05KHz - or after the second harmonic. It is proven that though we probably cannot hear these upper frequencies they do how ever influence modulation of the lower frequencies.
By increasing the sample rate to 192kHz

3rd Harmonic 44kHz
4th Harmonic 55kHz
5th Harmonic 66kHz
6th Harmonic 77kHz
7th Harmonic 88kHz


The signal can retain these upper audio frequecies and so retain more of the original spectrum and influence.


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Barish
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Re: What is the point in 192kHz? new [Re: DCompton]
      #245432 - 31/01/06 02:08 AM
Quote DCompton:

The signal can retain these upper audio frequecies and so retain more of the original spectrum and influence.




Read the link in the middle, this was replied to earlier on:

Quote Barish:

In fact, below thread could be a good starter for you:

http://recforums.prosoundweb.com/index.php/t/2997/0

and this "high frequency transients fallacy":

http://recforums.prosoundweb.com/index.php/t/4097/0


and this "EQ for 192kHz sampling":

http://recforums.prosoundweb.com/index.php/t/2666/0


B.




If an ear can not hear the root frequency above, say, 22kHz, it can not hear the harmonics and transients above 22kHz either.

Period.


You are making us write the same things over... and over... and over... again.


PLEASE READ THOROUGHLY BEFORE POSTING.


...Including the links.

B.


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Barish
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Re: What is the point in 192kHz? new [Re: Michael Harrison]
      #245436 - 31/01/06 02:11 AM
Quote Michael Harrison:

There is no approximation. Frequencies below Nyquist are reproduced accurately. Frequencies above Nyquist are not reproduced.





Everyone should write this on a big piece of paper and frame it on their studio wall.

B.


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Michael Harrison
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Re: What is the point in 192kHz? new [Re: Barish]
      #245448 - 31/01/06 06:06 AM
I have.






Where's yours??

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Pangloss
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #245484 - 31/01/06 09:24 AM
I've kept out of this thread so long and fortunately I've learned a lot.

One question though (Hugh? Barish? etc.)

The algorithms used by the reconstruction filters - are they open source? I.e. is there a "correct" implementation, one that can be found in a numerical recipes-type text book.

Or are they proprietry? That is to say, are some manufacturers' reconstruction filter designs inherently better than others (i.e. do some more intelligently interpolate between samples than others).

Any suggested reading appreciated. Thanks.


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Dishpan



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Re: What is the point in 192kHz? new [Re: Barish]
      #245522 - 31/01/06 10:42 AM
> There is no approximation. Frequencies below Nyquist are reproduced accurately. Frequencies above Nyquist are not reproduced.
> Everyone should write this on a big piece of paper and frame it on their studio wall.

But it's wrong, there IS approximation, as we're restricted by limited bit-depth, and higher sample rates CAN give a better approximation of frequencies at <1/2 sample rate, although the differences are probably inaudable.

Edited by kris (31/01/06 10:43 AM)


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James PerrettModerator



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Re: What is the point in 192kHz? new [Re: Pangloss]
      #245524 - 31/01/06 10:45 AM
Quote Pangloss:

I've kept out of this thread so long and fortunately I've learned a lot.

One question though (Hugh? Barish? etc.)

The algorithms used by the reconstruction filters - are they open source? I.e. is there a "correct" implementation, one that can be found in a numerical recipes-type text book.

Or are they proprietry? That is to say, are some manufacturers' reconstruction filter designs inherently better than others (i.e. do some more intelligently interpolate between samples than others).





Finally someone drags this thread beyond kindergarten level.

I'm not a DSP guru but I understand that this is where things start to get interesting. Modern convertors work at much higher frequencies than the final sampling frequency which means that the reconstruction filter is implemented digitally with only a very simple RC filter in the analogue domain. Different designers make different choices. Some choose a slightly lower corner frequency with a shallower slope while others choose a higher corner frequency with a steeper slope. The steeper slope is possibly harder to implement and you may have to put up with a small amount of frequency response ripple in the passband. There are also issues of phase to think about - whether you go linear phase or minimum phase.

Look for papers by Steve Green from Cirrus or Richard Kulavik at AKM - they're at the cutting edge of convertor filter design.

Cheers

James.

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Lighthouse_Mastering



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Re: What is the point in 192kHz? new [Re: Barish]
      #245525 - 31/01/06 10:47 AM
Quote Barish:


You are making us write the same things over... and over... and over... again.


PLEASE READ THOROUGHLY BEFORE POSTING.


...Including the links.

B.




Barish,

It is obvious when you look at it (if you take the time), but many people don't believe the obvious anymore. In this "Quantum" world people are sceptical about scientific truths. There has obviously been problems with digital recording, processing and playback. Many people believe that the answers lie in the sampling rate. They feel if the maths don't add up, then the maths must be incomplete like classical physics, etc, etc. You are not going to win any arguments by hitting them again and again with the maths.

I personally have my own beliefs on why digital has often failed to satisfy, (not sampling rates) but I will keep those to myself.

Cheers

Dave

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Pangloss
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #245561 - 31/01/06 11:43 AM
Thanks James - that's my internet research project for the afternoon set out then.


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #245673 - 31/01/06 02:16 PM
Quote kris:

But it's wrong, there IS approximation, as we're restricted by limited bit-depth, and higher sample rates CAN give a better approximation of frequencies at <1/2 sample rate, although the differences are probably inaudable.




I can't agree with this I'm afraid. Sure, quantisation is an imperfect process and the resolution is determined to a large dgree by the word length used. But changing the sample rate has no effect on the wordlength, and thus it can not alter what you refer to (incorrectly) as 'approximation of frequencies at >1/2 sample rate'

hugh

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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Pangloss]
      #245690 - 31/01/06 02:38 PM
Quote Pangloss:

The algorithms used by the reconstruction filters - are they open source? I.e. is there a "correct" implementation, one that can be found in a numerical recipes-type text book. Or are they proprietry? That is to say, are some manufacturers' reconstruction filter designs inherently better than others (i.e. do some more intelligently interpolate between samples than others).




Tricky question to answer. This is the cutting edge of the art and science. I'm not very knowledgable in the intricate details of converter design I'm afriad, but I don't think there is anything around by the way of open-source reconstruction filters and the like. Having said that, though, the principles involved are all pretty standard stuff.

Perhaps the best place to seek more information is the converter chip manufacturer websites. You'll be able to see spec sheets there with loads of frequency ploys showing the different filter characteristics used. AKM, Crystal, Cirrus, Burr Brown and so on all use slight variations on the themes.

The high end converter box makers then choose specific chips over others because they feel they sound better -- largely because of the way the filtering has been implemented. Read my review of the Benchmark DAC1 for a little insight into this -- I had a fascinating chat with the designer about converter filter issues and some of that chat made it into the review.

One of the main issues is that of out of band noise -- probably more so than the details of pass band ripple and stop band slopes, in fact.

Most, if not all, audio converters these days are of the delta-sigma type, which operate at a very high sample rate with low bit depth, and then use decimation (essentially a digital filtering process) to translate to a lower sample rate and much higher wordlength.

Part of this process generates a lot of quantisation noise which is piled up above 20kHz. Exactly how much, and how it is shaped spectrally, varies a lot between different chip-makers. At the last AES one chip maker was making a big song and dance at its show stand about how much less ultrasonic noise it produced than its competitors.

Hugh

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to-pse



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #245694 - 31/01/06 02:39 PM
Actually what probably makes 96 or 192 khz superior to plain
44.1khz sampling is not the fact that the sampled data is more accurately reproduced but rather the fact,
that when working on the recorded data in the DAW, the
DSP-algorithms work far nicer if the sampling-rate is
higher. This is the reason why quite a few VST-developers
resample stuff from 44.1 khz upwards internally for
processing and later on convert it back to 44.1.

Obviously this concept is a little bid absurd if you
have a chain of 4 VSTs on one track each interpolating
and decimating, causing much more load than necessary.

I really don't understand why the developers of DAW-Hosts
like Steinberg or Apple don't support some kind of
hybrid-mode, where sampling & playback is done with 44.1khz,
but the processing-chain itself is run at a higher sample-rate. This would prevent multiple chained SRCs and still
allow effects to use the increased bandwidth for better
DSP operation...

Tobias


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Anonymous
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Re: What is the point in 192kHz? new [Re: James Perrett]
      #245706 - 31/01/06 02:51 PM
Quote:

James Perrett:
Different designers make different choices. Some choose a slightly lower corner frequency with a shallower slope while others choose a higher corner frequency with a steeper slope. The steeper slope is possibly harder to implement and you may have to put up with a small amount of frequency response ripple in the passband. There are also issues of phase to think about - whether you go linear phase or minimum phase.




And no one filter will work perfectly with every programme source in every configuration, at every sample rate.

In their newer A-D converters, dCS have made a move towards addressing this by allowing the user to choose from 4 different anti-aliasing filters and three different types of noise shaping according to what suits the project in hand. Very effective they are too. The D-A converters also allow you a bit of choice with their filters letting you chose to trade off transition curves/impuse responses/stereo imaging against Nyquist imaging. Again, a useful feature and not as subtle as one might expect. It's still possible to vanish up your own backside when comparing filters and noise shaping though!

This isn't particularly a new thing - In the 1990s, Harmonia Mundi Digital (early Daniel Weiss gear) allowed the user to select filters, noise shaping and dither algorithms in their 102 mastering processor, and Digital Integration and ADT both made really dinky SRC boxes which let you choose from loads of different dither types and filters. On a simpler level, things like Apogee UV20/UV22/etc. and all the multiplicity of dither options now available in mastering/recording software all give the ability to optimise conversions to different jobs via various presets and selectable options.


There's some interesting general reading on the Tech Papers section of the dCS website.


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Lighthouse_Mastering]
      #245708 - 31/01/06 02:57 PM
Quote Lighthouse_Mastering:

There has obviously been problems with digital recording, processing and playback. Many people believe that the answers lie in the sampling rate.




You are right, of course. There have been problems with the first few commercial generations of digital equipment. In the main I think we can largely blame the marketing hype over the engineering reality.

Some of the first experimental machines operated at 60kHz sample rates, and they showed enormous promise -- personally I think that is the rate that should have been retained from the start. Sadly, Sony's cost-cutting to use existing video recording hardware as the data storage device imposed 44.1kHz on us, and the rest is history.

But the real problem with early digital equipment was that of the inherent practical problems associated with the anti-alias and reconstruction filtering, and the limited bit depth (many so-called 16 bit machines were actually struggling to achieve 14 bit performance, for example). It was the practical implementation of the theory that was flawed, not the theory itself. Indeed, the theory has been proven to be complete and accurate coutless times, and in countless industries -- not just audio.

If the sampling theorum was flawed we wouldnb't have telephone systems, planes would fall out of the sky on a regular basis, TV and films wouldn't work, and so on!

As far as audio is conerned, though, things have come on in leaps and bounds in recent years. The introduction of oversampling and digital filtering cured most of the practical problems with analogue anti-alias and reconstruction filtering -- and delta-sigma techniques have improved the situation further still, allowing the move to 24 bit word lengths along the way. We also now have infinitely better clock accuracy and stability, better interface standards and much more besides.

The first practical magnetic tape recorders started to appear in the early 1940s, but the technology didn't reach the peak of its performance potential until the late 1980s. That's a forty year development curve.

The first practical digital audio equipment started to appear in the early 1980s -- that's only 25 years ago. For a new technology I think it is mighty impressive and I wouldn't want to turn the clock back. Although I'm not saying we have an entirely perfect implementation of the technology yet -- or that it necessarily sounds the same -- although that particular aspect cuts both ways, of course.

Quote:

They feel if the maths don't add up, then the maths must be incomplete like classical physics, etc, etc. You are not going to win any arguments by hitting them again and again with the maths.




Er... but the maths do add up. Of that there is nodoubt whatever. The problem is that the maths involved relies on concepts and techniques which are above the understanding of the vast majority of users.

Few people understand the thermo-dynamic equations involved in defining how petrol burns in a combustion chamber and makes a car engine go faster.... doesn't stop them from using the car to get to work though! For some strange reason, people seem to want to argue about digital audio technology even though they don't undertsand it, yet not about the merits of fuel additives and octane ratings. Maybe I'm on the wrong forum

hugh

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Dishpan



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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #245713 - 31/01/06 03:10 PM
/Groans

> I can't agree with this I'm afraid. Sure, quantisation is an imperfect process and the resolution is determined to a large dgree by the word length used. But changing the sample rate has no effect on the wordlength, and thus it can not alter what you refer to (incorrectly) as 'approximation of frequencies at >1/2 sample rate'

I didn't incorrectly refer to frequencies of >1/2 sample rate, you incorrectly quoted me . I said frequencies of <1/2 sample rate and it's easy to show this mathmatically, especially with signals represented with low bit-depths.

Here's a simple example, take a 1-bit system (or indeed a signal which only modulates the lowest bit) with a 5hz sampling rate. A 2.5hz sine wave could clearly be encoded as 1010101. Now show me how 2.4, 2.3, 2.2, 2.1 or 2hz sine waves (ALL of which fall below the Nyquist limit) can be encoded.... Do you think a 100hz sampling rate could reproduce these frequencies more accurately?

Now of course digital system don't work with 1-bit precision, and this error is inversely proportional to bit-depth, so is almost certainly inaudible. That however doesn't change the fact that's it's still there, and higher sampler rates can reduce it.


> This is a common argumant, but is technically incorrect I'm afraid. If you re-assess the Nyquist theorem you quote, you'll see that the signal can be fully reconstructed -- without any waveshape distortion and with perfect accuracy -- provided there are at least two samples per cycle. The maths proves this without any doubt whatever.

No, provided there are two samples of INFITINE PRECISION per cycle, something no digital system will ever have...


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Stan



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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #245725 - 31/01/06 03:38 PM
This thread gets better and better.
Any chance of an SOS article on the merits of 192kHz.
e.g. A fact and fiction guide for dummies like me.

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James PerrettModerator



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Re: What is the point in 192kHz? new [Re: Dishpan]
      #245758 - 31/01/06 04:45 PM
Quote kris:



Now of course digital system don't work with 1-bit precision,




Err - yes they do... it would be well worth doing a little reading on how digital audio systems really work before trying to tell us what is wrong with them. One bit sampling is extremely common - bitstream, MASH and DSD are all names of one bit sampling systems used in digital audio.

Cheers

James.

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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #245763 - 31/01/06 04:54 PM
Quote kris:

I didn't incorrectly refer to frequencies of >1/2 sample rate, you incorrectly quoted me .




Apologies for the misquote. Fingers faster than brain sometimes...

Quote:

Here's a simple example, take a 1-bit system (or indeed a signal which only modulates the lowest bit) with a 5hz sampling rate. A 2.5hz sine wave could clearly be encoded as 1010101. Now show me how 2.4, 2.3, 2.2, 2.1 or 2hz sine waves (ALL of which fall below the Nyquist limit) can be encoded.... Do you think a 100hz sampling rate could reproduce these frequencies more accurately?




Sorry to say it yet again, but your view on this is far too simplistic. The maths are complex, and hard to understand if its not your thing (and I'm no mathematician), but they aren't wrong! Once again, the flaw in your example is the lack of the equivalent of the reconstruction filtering.

Quote:

Now of course digital system don't work with 1-bit precision




Er... talk to Sony about that and mention DSD...

hugh

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Dishpan



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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #245770 - 31/01/06 05:09 PM
> Sorry to say it yet again, but your view on this is far too simplistic.

My views on it certainly aren't simplistic, I'm simply trying to word it that way so people can understand.... and I'm obviously failing.... miserably.... as usual.....

> The maths are complex, and hard to understand if its not your thing (and I'm no mathematician), but they aren't wrong!

Which maths aren't wrong? Nyquist certainly wasn't wrong, but he didn't say you could perfectly recreate all frequencies at <1/2 sample rate when your sampled values were quantised!


> Once again, the flaw in your example is the lack of the equivalent of the reconstruction filtering.

No, the flaw is that the Nyquist theorem requires a higher sampling resolution (not rate) than a low-bit depth signal can provide (in fact to perfectly recreate the source would require an infinite bit depth). This has nothing to do with reconstruction filtering!


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Lighthouse_Mastering



Joined: 13/12/05
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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #245784 - 31/01/06 05:33 PM
Quote Hugh Robjohns:


But the real problem with early digital equipment was that of the inherent practical problems associated with the anti-alias and reconstruction filtering, and the limited bit depth (many so-called 16 bit machines were actually struggling to achieve 14 bit performance, for example). It was the practical implementation of the theory that was flawed, not the theory itself.




The real problem was the need to achieve a flat 20-20K freq response, yet avoid the aliasing problems. “Brick wall” filters sounded horrible, and digital filtering and oversampling seemed necessary. I think we are still suffering, and our engineering solutions have only moved us sideways. If you listen to early multibit converters, they have qualities that modern Delta Sigmas have lost. Oversampling, Upsampling, and Delta Sigma conversion all have their own sonic signature, that we now equate to the digital sound. Sure we have lost the hard glassy sound of the early digital, but we have gained other forms of distortion.

Quote:


Indeed, the theory has been proven to be complete and accurate coutless times, and in countless industries -- not just audio.




Agreed, the theory is sound, and I do not think that very high sampling rates are by themselves the answer. The one advantage that I believe high sampling rates allow, are the movement of the aliasing products higher up the frequency range, which allows for gentle analog filtering. I don’t believe they allow us to hear any “missing information”.

Quote:


As far as audio is conerned, though, things have come on in leaps and bounds in recent years. The introduction of oversampling and digital filtering cured most of the practical problems with analogue anti-alias and reconstruction filtering -- and delta-sigma techniques have improved the situation further still, allowing the move to 24 bit word lengths along the way. We also now have infinitely better clock accuracy and stability, better interface standards and much more besides.




Each of these “advances”, has brought its own set of problems. Oversampling and digital filtering were solutions to aliasing problems with low sample rates. They should not be present in higher sample rate based digital audio. I am sure that a 96Khz based system using no oversampling or digital filtering, and based around high quality multibit converters would sound amazing. Unfortunately we cannot break free from the solutions to our past mistakes, and digital is always likely to sound nothing like analog.

Quote:


Er... but the maths do add up. Of that there is nodoubt whatever. The problem is that the maths involved relies on concepts and techniques which are above the understanding of the vast majority of users.





I agree, the maths do add up, but there are people who are always going to believe that it is incomplete. The fact is, if the maths IS right, then where is the problem? Could it be that our implementation still stinks

Quote:


Maybe I'm on the wrong forum

hugh




No, from what I have seen, I think you do a great job at bringing some common sense and knowledge to discussions that are often missing in those departments.

Cheers

Dave

--------------------
Lighthouse Mastering


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Feefer
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OT: PC new [Re: Hugh Robjohns]
      #245831 - 31/01/06 07:06 PM
Quote Hugh Robjohns:

The problem is that the maths involved relies on concepts and techniques which are above the understanding of the vast majority of users.

*snip*

For some strange reason, people seem to want to argue about digital audio technology even though they don't undertsand it...





In this age of wide-spread political correctness, everyone apparently has a right to feel good about themselves, and everyone's ego deserves a lil' message. The line between facts and opinions has become blurred in so many people's mind to the point where they don't consider the difference, and all expressions are considered equally important and valid, all deserving of protection.

It doesn't matter if someone actually has FACTS on their side, or if they actually have any knowledge or experience on the subject matter: everyone with a modem is "entitled to an opinion". We can't let FACTS stand in the way of what we believe, can we?

It's gotten to the point where some school administrators discourage teachers from marking students' exams with a red ink pen, since the red ink is considered "too harsh and traumatizing". Eventually, teachers no doubt will feel compelled to erase the student's incorrect answer, and simply write in the proper answer, since you don't want to bruise the little punter's fragile ego by pointing out they're wrong.

Obviously, there is a price to be paid for subordinating objective facts to desires for diplomacy and political correctness; namely, a dummying-down of our culture.

Chris

--------------------
1.5GHz Al 17" Powerbook G4 (2.0GB RAM, Hitachi 60GB 7,200 rpm drive), running Logic Pro 7 under OSX 10.4.5


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Stan



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Re: OT: PC new [Re: Feefer]
      #245850 - 31/01/06 07:28 PM
Quote Feefer:



Obviously, there is a price to be paid for subordinating objective facts to desires for diplomacy and political correctness; namely, a dummying-down of our culture.

Chris



Did I tempt this response with my 'for dummies' suggestion?
Not fair.

--------------------
.. is this thing on?

Edited by Stan (31/01/06 07:29 PM)


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Feefer
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Re: OT: PC new [Re: Stan]
      #246010 - 31/01/06 11:57 PM
Quote Stan:

Did I tempt this response with my 'for dummies' suggestion? Not fair.




No, you didn't tempt the response. Education is fine.

Just realize there's a big difference between writing a book for dummies vs. letting all the dummies author a chapter in the book! And believe me: I won't be writing a chapter in that book, as some of the people here have gotten in way over my head (and I ain't in a learning mood, right now).

Chris

--------------------
1.5GHz Al 17" Powerbook G4 (2.0GB RAM, Hitachi 60GB 7,200 rpm drive), running Logic Pro 7 under OSX 10.4.5


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246013 - 01/02/06 12:04 AM
Quote kris:

>My views on it certainly aren't simplistic, I'm simply trying to word it that way so people can understand.... and I'm obviously failing.... miserably.... as usual.....




Well, I've got to say in all the years I've been dealing with digital audio in one form or another I have never once come across this argument before. I'm not convinced by it, but I'm open minded enough to look into it further if you can suggest where to go looking....

Quote:

Nyquist certainly wasn't wrong, but he didn't say you could perfectly recreate all frequencies at <1/2 sample rate when your sampled values were quantised!




True enough, he wasn't dealing with quantisation. But I'm still struggling to see how quantisation noise can affect sampling accuracy in the way you claim.

Quote:

No, the flaw is that the Nyquist theorem requires a higher sampling resolution (not rate) than a low-bit depth signal can provide (in fact to perfectly recreate the source would require an infinite bit depth).




Hmmm....

hugh

--------------------
Technical Editor, Sound On Sound


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Lighthouse_Mastering]
      #246021 - 01/02/06 12:21 AM
Quote Lighthouse_Mastering:

“Brick wall” filters sounded horrible, and digital filtering and oversampling seemed necessary.




Yes, most of the analogue brickwall filters sounded grim, but we still have them -- it's just that they are in the digital domain now where we can make them more nearly 'perfect' than we ever could with analogue designs.

Quote:

Sure we have lost the hard glassy sound of the early digital, but we have gained other forms of distortion.




Very true. No such thing as a free lunch. Delta-sigma converters do have their own unique set of issues to deal with... but on the whole they come closer to the holy grail than anything else so far.

Quote:

I am sure that a 96Khz based system using no oversampling or digital filtering, and based around high quality multibit converters would sound amazing.




But it can't be done with current technology. It was hard enough getting multibit converters to operate with 16 bit accuracy, and it really was rocket science trying to squeeze 20 bits out of them -- and that was at 48kHz. Variations on the delta-sigma theme coupled with oversampling and digital filters is the only practical way at the moment.

Quote:

digital is always likely to sound nothing like analog.




True... but is that really a bad thing? I loathe the digital v analogue comparisons. They are pointless. What we should be comparing is analogue and digital against the source. And if you do that, I'm happy these days that good 24/96 digital wins every single time -- you get back exactly what you put in as far as my ears can tell. 16/44.1 is close but the top end tends to sound a little congested. Analogue comes back sounding warm and fuzzy. Not unpleasant, but not accurate.

Analogue is great and will be with us for a long time to come because of its simplicity and sound character, but let's not confuse it with precision or accuracy.

Quote:

The fact is, if the maths IS right, then where is the problem? Could it be that our implementation still stinks




I wouldn't go as far as saying it stinks, but agree with you that most budget to mid level implementations are still lacking in various small but significant ways. The really high end stuff is stunningly good, but it will be a while before that quality reaches our daily lives.

Technology advances at quite a pace though. Compare cheap mixer mic amps now with ten years ago and you'll be shocked with how bad they were back then! Compare a modern cheap mixer mic amp with a good high end outboard one, and you'll be shocked again at how limited they still are!

Hugh

--------------------
Technical Editor, Sound On Sound


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Anonymous
Unregistered




Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #246161 - 01/02/06 10:42 AM
I hate to say this Hugh, but you're really letting down the whole forum with your inappropriate attire this morning. A chap should keep his evening wear for the evening.


(Incidentally, does your dinner jacket have the regulation BBC leather elbow patches?)



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Pangloss
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #246169 - 01/02/06 10:57 AM
That is an interesting point that Lighthouse_Mastering is making regarding the quantisation of the available samples. Fitting some sort of sine curve over infinitely quantised samples, while non-trivial, at least looks fairly do-able. However, if each of those samples has a small quantisation error in the time direction then fitting a curve starts to look much more like a statistical fit and therefore more subjective? No? Isn't there going to be some uncertainty in the phase accuracy whichever sine wave you choose?

Edited by Pangloss (01/02/06 10:58 AM)


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Lighthouse_Mastering



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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #246172 - 01/02/06 11:03 AM
Quote Hugh Robjohns:

Delta-sigma converters do have their own unique set of issues to deal with... but on the whole they come closer to the holy grail than anything else so far.




We will have to disagree there. The distortions that delta sigmas introduce are far more incidious than any problems with multibit

Quote:

Quote:

I am sure that a 96Khz based system using no oversampling or digital filtering, and based around high quality multibit converters would sound amazing.




But it can't be done with current technology. It was hard enough getting multibit converters to operate with 16 bit accuracy, and it really was rocket science trying to squeeze 20 bits out of them -- and that was at 48kHz. Variations on the delta-sigma theme coupled with oversampling and digital filters is the only practical way at the moment.




You must be refering to AD conversion, because there have been plenty of 24bit mutibit DA converters capable of running at high sample rates. I am sure that the dirth of multibith AD's is due to lack of demand (and the cost), and not a technical issue. Surely the best we can get out of any conversion system is just over 120db.

Quote:

Quote:

digital is always likely to sound nothing like analog.




True... but is that really a bad thing? I loathe the digital v analogue comparisons. They are pointless. What we should be comparing is analogue and digital against the source. And if you do that, I'm happy these days that good 24/96 digital wins every single time -- you get back exactly what you put in as far as my ears can tell. 16/44.1 is close but the top end tends to sound a little congested. Analogue comes back sounding warm and fuzzy. Not unpleasant, but not accurate.




Sorry, I do not want to drag this into an analog vs digital debate either. The point is that the conversion processes should be transparent. If you take an analoge recording and convert it to digital, and then convert it back, it should not be fundamentally transformed. The issue for me is that with analog processing, each step causes a gradual degradation, whilst the conversion to/from digital is a much more fundamental change.

Quote:


Quote:

The fact is, if the maths IS right, then where is the problem? Could it be that our implementation still stinks




I wouldn't go as far as saying it stinks, but agree with you that most budget to mid level implementations are still lacking in various small but significant ways. The really high end stuff is stunningly good, but it will be a while before that quality reaches our daily lives.




I don’t believe that the sonic differences between esoteric and mid/budget converters can be put down to the conversion or filter technology. It is more to do with the quality of the analog circuits, the power supply, and the overall precision of the implementation. Even so, the best digital processing equipment is in my opinion flawed.

Quote:


Technology advances at quite a pace though. Compare cheap mixer mic amps now with ten years ago and you'll be shocked with how bad they were back then! Compare a modern cheap mixer mic amp with a good high end outboard one, and you'll be shocked again at how limited they still are!

Hugh




There is a limit to what you can do within a budget. Good quality analog stages and power supplies are expensive, so is the research to get the most out of technology.
It is easy to see how cheap mixers have been improved, but I cannot see where the improvements in digital are going to come from. I think we missed a turn, and are proceeding up a dead end. The maths is perfect, we cannot improve the signal to noise, and higher sampling rates (in the current implementations) have not brought the promised improvement. What is left to work on?

Since the best quality digital replay I have heard (by ten country miles), was from an antiquated Multibit DAC, with no digital filtering or oversampling, I cannot see how further digital filter development or advances with delta sigma conversion are going to help.

Dave

--------------------
Lighthouse Mastering


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Barish
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246178 - 01/02/06 11:14 AM
Quote kris:

No, the flaw is that the Nyquist theorem requires a higher sampling resolution (not rate) than a low-bit depth signal can provide (in fact to perfectly recreate the source would require an infinite bit depth). This has nothing to do with reconstruction filtering!






Nyquist theorem is not about the dynamic range, but about the frequency content.

The dynamic range of human hearing: 110dB on average.

24 bits: 144dB, all covered and then some.

16 bits: 96dB, quite an adequate range if used properly, considering the effects of correct dithering.


Problem solved. What are you talking about?


Sorry Hugh, I'm not really convinced that open-minded approach to give everyone's opinion a benefit of doubt is really working here. This is like giving Hitler a benefit of the doubt that he might be up to something right.


I'm off.


B.


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Pangloss
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #246291 - 01/02/06 02:33 PM
(sorry Lighthouse - just re-read the thread and it looks like I was putting words in your mouth there. Quoting the wrong person).


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Lighthouse_Mastering



Joined: 13/12/05
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Re: What is the point in 192kHz? new [Re: Pangloss]
      #246363 - 01/02/06 04:37 PM
Quote Pangloss:

(sorry Lighthouse - just re-read the thread and it looks like I was putting words in your mouth there. Quoting the wrong person).




That's alright Pangloss. I was actually infering to the issue you mentioned, I just had not got technical. When I saw your post, I thought you were very insightful to infer the time domain quantisation distortion. Digital filtering, over(up)sampling and delta sigma conversion all cause distortion in the time domain, as I am sure does much DSP based processing.

Dave

--------------------
Lighthouse Mastering


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Barish]
      #246370 - 01/02/06 04:57 PM
Quote Barish:

Sorry Hugh, I'm not really convinced that open-minded approach to give everyone's opinion a benefit of doubt is really working here.




I'm even slightly not convinced, as I said. But he seems adamant so the least I can do is recheck the concept -- as much for my own peace of mind as anything else. I see no hint of any suggested references yet though...

hugh

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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Lighthouse_Mastering]
      #246394 - 01/02/06 05:35 PM
Quote Lighthouse_Mastering:

We will have to disagree there. The distortions that delta sigmas introduce are far more incidious than any problems with multibit




Fair enough. Disagreement it is It's a different set of problems -- more time domain-related than frequency/amplitude domain. Idle tones and limit cycles were a major problem in some systems, but even that seems to have been largely gripped in the latest designs.

Quote:

You must be refering to AD conversion, because there have been plenty of 24bit mutibit DA converters capable of running at high sample rates.




I'm struggling to think of any... pretty much everything I can think of uses some variation on the theme of a low wordlength delta-sigma topology (ie. 3, 4, or 5 bits in a highly overampled D-S system).

Quote:

I am sure that the dirth of multibith AD's is due to lack of demand (and the cost), and not a technical issue. Surely the best we can get out of any conversion system is just over 120db.




My understanding is that it is very much a technical issue, which is why I made the statement in the first place And yes, 120dB or there abouts is pretty much as good as the dynamic range gets with current technology.

Quote:

It is easy to see how cheap mixers have been improved...




Really? Compare the circuit design of the mic pre in an early Mackie mixer and the later XDR or Onyx circuits. The changes (on paper) are not that significant at all, yet the sound quality is leagues apart!

Quote:

but I cannot see where the improvements in digital are going to come from.




I expect a lot of people said the same thing when Sony were struggling to make 16 bit multibit converters work properly. And then Philips introduced oversampling. And then people found ways of making clocks far more stable. And then delta-sigma converters came along.... There will be numerous advances in the years to come -- mainly to do with the way the existing technology is implemented, but I dare say some clever new techniques will also be found. Just as the wow and flutter of tape transports and record players improved dramatically over decades. The concepts didn't change, but the ability to engineer better solutions improved.

hugh

--------------------
Technical Editor, Sound On Sound


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Dishpan



Joined: 01/09/04
Posts: 813
Re: What is the point in 192kHz? new [Re: Barish]
      #246397 - 01/02/06 05:43 PM
> Nyquist theorem is not about the dynamic range, but about the frequency content.

The Nyquist theorem requires that each point must be sampled accurately for it to work properly. If you can't accurately sample the lever of each point (and you can't at low bit-depths), the ONLY possible other way to give a better approximation of the input is to increase sampling rate.

The two ARE related.


> Problem solved. What are you talking about?

Barish, if you read my reply you'll see I actually said the differences are probably inaudable. That wasn't my point, the point is people are saying NO information is lost and there's NO approximation, when information IS lost due to limited bit-depth (and sample rates), and a high-sampling rate CAN reduce this loss of information.

BTW, yesterday (to convice myself I wasn't going mad) I also did the example I posted (as well as various frequency sweeps) in Wavelab, Sound Forge and Adobe Audition at a friends. The results were exactly as I expected, higher sample rates resulted in a better approximation of low bit-depth frequencies of <1/2 sample rate.

As I said though, the differences in the real-world are almost certainly inaudable (we've got no argument there!), but they're still there.


> Sorry Hugh, I'm not really convinced that open-minded approach to give everyone's opinion a benefit of doubt is really working here. This is like giving Hitler a benefit of the doubt that he might be up to something right.

If you're referring to me, I think it's totally uncalled for.

Cheers

Edited by kris (01/02/06 05:46 PM)


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PrinceXizor
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Joined: 30/01/04
Posts: 825
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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #246403 - 01/02/06 05:57 PM
I'd just like to say that this thread is chock full of good information. Hugh, bravo! (and you look good in evening attire...heh!).

Not singling out any one poster, but I'll say this. Sadly, at work, even my boss makes assumptions and forms opinions about tasks that are orders of magnitude more complex than they appear on the surface. It SEEMS so simple, yet rarely is.

As an aside, my brother is just finishing up his Math degree . He's still a little up in the air on what he's going to go though he's leaning toward theoretical as opposed to applied. Any suggestions on coursework that would lend itself to this type of situation (audio/frequency/sampling/etc. and the math's behind the field). I know he has at least a passing interest in audio.

Cheers!

P-X

--------------------
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James PerrettModerator



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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246405 - 01/02/06 06:04 PM
Quote kris:



Barish, if you read my reply you'll see I actually said the differences are probably inaudable. That wasn't my point, the point is people are saying NO information is lost and there's NO approximation, when information IS lost due to limited bit-depth (and sample rates), and a high-sampling rate CAN reduce this loss of information.






You really ought to get yourself a good text book on digital audio. You've just described oversampling which is a standard technique used in modern convertors.

Cheers

James.

--------------------
JRP Music - Audio Mastering and Restoration.
http://www.jrpmusic.net


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Lighthouse_Mastering



Joined: 13/12/05
Posts: 52
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246408 - 01/02/06 06:09 PM
Quote kris:

> Nyquist theorem is not about the dynamic range, but about the frequency content.

The Nyquist theorem requires that each point must be sampled accurately for it to work properly. If you can't accurately sample the lever of each point (and you can't at low bit-depths), the ONLY possible other way to give a better approximation of the input is to increase sampling rate.

The two ARE related.




Sorry Kris, but can you explain this a bit more clearly. What do you mean by nor sampling acurately, and low bit-depths?

Quote:


> Problem solved. What are you talking about?

Barish, if you read my reply you'll see I actually said the differences are probably inaudable. That wasn't my point, the point is people are saying NO information is lost and there's NO approximation, when information IS lost due to limited bit-depth (and sample rates), and a high-sampling rate CAN reduce this loss of information.





Again, I think you need to go into more depth in your arguement. I cannot see how there is information loss.

Dave

--------------------
Lighthouse Mastering


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Dishpan



Joined: 01/09/04
Posts: 813
Re: What is the point in 192kHz? new [Re: James Perrett]
      #246409 - 01/02/06 06:10 PM
> You really ought to get yourself a good text book on digital audio. You've just described oversampling which is a standard technique used in modern convertors.

I've got plenty of good books on digital audio James. Oversampling requires a reasonable amount of resolution to work succesfully and I'm talking about low-level signals where you DON'T have a lot of sampling resolution (although this distortion occurs at all bit-depths, it's level is inversely proportional to bit depth).


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Lighthouse_Mastering



Joined: 13/12/05
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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #246417 - 01/02/06 06:23 PM
Quote Hugh Robjohns:

Quote:

You must be refering to AD conversion, because there have been plenty of 24bit mutibit DA converters capable of running at high sample rates.




I'm struggling to think of any... pretty much everything I can think of uses some variation on the theme of a low wordlength delta-sigma topology (ie. 3, 4, or 5 bits in a highly overampled D-S system).





Off the top of my head, Burr Brown make a 24bit high sample rate capable multibit DAC, and I know that there are others.

Quote:

Quote:

I am sure that the dirth of multibith AD's is due to lack of demand (and the cost), and not a technical issue. Surely the best we can get out of any conversion system is just over 120db.




My understanding is that it is very much a technical issue, which is why I made the statement in the first place And yes, 120dB or there abouts is pretty much as good as the dynamic range gets with current technology.




I am sure it is just a supply demand thing. The only reason there are multibit DAC's still available is because they are used in the audiophile market, and they don't do ADC's.

Quote:

Quote:

but I cannot see where the improvements in digital are going to come from.




I expect a lot of people said the same thing when Sony were struggling to make 16 bit multibit converters work properly. And then Philips introduced oversampling. And then people found ways of making clocks far more stable. And then delta-sigma converters came along.... There will be numerous advances in the years to come -- mainly to do with the way the existing technology is implemented, but I dare say some clever new techniques will also be found. Just as the wow and flutter of tape transports and record players improved dramatically over decades. The concepts didn't change, but the ability to engineer better solutions improved.

hugh




I agree that digital is better today than it was 20yrs ago, but just not as good as it could be. Good to see you are an optimist.

Dave

--------------------
Lighthouse Mastering


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Dishpan



Joined: 01/09/04
Posts: 813
Re: What is the point in 192kHz? new [Re: Lighthouse_Mastering]
      #246435 - 01/02/06 06:49 PM
> Sorry Kris, but can you explain this a bit more clearly. What do you mean by nor sampling acurately, and low bit-depths?

Dave, I'll give the example again and I'll attempt to make it clearer. by low bit-depths, I'm talking about frequencies that modulate only the last few bits in a digital system (i.e. at a very low level). For example, there could be frequencies that only modulate the lowest bit (of course there's dither, but I'm not discussing that here). A simple example would be at the tail end of a fade out.

So, let's say you sample at 10hz and you input a 5hz sine-wave (remember, in this example we're using a 1-bit system).

The ONLY possible way it can accurately be encoded is 010101010101 etc.... (of course we have a zero crossing point in reality, but I'm trying to make it simple so please don't hold that against me).

Now try a 4hz sine-wave. We have a problem, 101 is a 5hz sine-wave (after reconstruction), but 110011 would be a 2.5hz sine-wave. It's therefore IMPOSSIBLE to accurately sample this 4hz sine waves, despite the fact it falls below the nyquist limit.

Now Hugh makes a good point about the reconstruction filter taking care of this, but I'm afraid it's NOT applicable here because the filter doesn't have sufficient input resolution to produce anything like a valid output!! If it can only see a 1 followed by a 0, how can it possibly know the input wasn't simply a 5hz sine-wave?

Now take a 100hz sampling rate with the same input. 5hz could be 10x1s, followed by 10x0s. 4hz could be 12x1s followed by 13x0s.

Despite the fact that ALL freqencies are below the Nyquist limit in both cases, the higher sampling rate gives us a better approximation of the same source.

Now as we all know, we work with 16/24 bit systems, so this error is almost certainly inaudable (as it decreases exponentially with bit-depth), but it's still there!

Anyway, I'm obviously in a minority of one here (not for the first time), so it's probably best if I leave it there, although it would be nice to know which part of the above people think erroneous (apart from "all of it!" ). Oh and I think it's the first time I've ever been compared with Hitler!

Take care


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coool



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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246509 - 01/02/06 08:43 PM
kris, please please dont be offended, i have had this exact same conversation from yr point of view about 2 yrs ago now, and i got everyones backs up the same as youve done. i got pointed in the direction of some helpful links like you, and i tried to follow it up, i really did. but i CANT get me head round the maths, so now i just accept that it works, more bits + higher resolution = better sound, and the only way of judging that is with yr ears .. and thats all there is to it, just cos we dont get the equations doesnt mean we is thick - you really cant say the maths is wrong cos you dont understand it. you say you are trying to make it simple, thats the problem it just IS NOT simple

cheer up - make some music instead of worrying about reconstruction filters and that nasty little nyquist man

oh and as for comparing YOU to hitler, i think HE shouted a lot, thought he was really clever and called people he didnt like 'subhuman' ... remind you of anyone else around here ?

grainger


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Barish
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246557 - 01/02/06 10:26 PM
Quote kris:

If it can only see a 1 followed by a 0, how can it possibly know the input wasn't simply a 5hz sine-wave?





Have you ever taken a third, fourth or fifth degree function and taken its derivative, and then taken the derivative of that derivative, and another derivative from that derivative, and then taken the integral of that derivative, anthen another integral of the result, and another integral of that result and compared the final result with the original function in your life?

I'm assuming that you know how to take derivatives and integrals, judging by your cunning attitude about this subject.

B.


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Steve Hill
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Re: What is the point in 192kHz? new [Re: Barish]
      #246573 - 01/02/06 10:58 PM
Quote Barish:

Quote kris:

If it can only see a 1 followed by a 0, how can it possibly know the input wasn't simply a 5hz sine-wave?





Have you ever taken a third, fourth or fifth degree function and taken its derivative, and then taken the derivative of that derivative, and another derivative from that derivative, and then taken the integral of that derivative, anthen another integral of the result, and another integral of that result and compared the final result with the original function in your life?

I'm assuming that you know how to take derivatives and integrals, judging by your cunning attitude about this subject.

B.




Barish, respect to you for your patience, but 155 posts on I've just lost the will to live on this topic!

If or when I can hear a discernible difference (or when my clients tell me it matters to them), I'll invest in it. Unless "it" is a stupid price.

Until then, as Shakespeare put it, the rest is silence.

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Dishpan



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Re: What is the point in 192kHz? new [Re: Barish]
      #246581 - 01/02/06 11:10 PM
> Have you ever taken a third, fourth or fifth degree function and taken its derivative, and then taken the derivative of that derivative, and another derivative from that derivative, and then taken the integral of that derivative, anthen another integral of the result, and another integral of that result and compared the final result with the original function in your life?

> I'm assuming that you know how to take derivatives and integrals, judging by your cunning attitude about this subject.

Barish yes I've studied calculus, but I really don't see the need for your hostile tone here, I'm not being agressive at all.

Anyway, a 1-bit waveform has no slope, it moves instantly from 0 to 1, so why in this case would derivatives help?

EDIT: Steve, yeah I think we've got as far as we're going to go on this one.

Edited by kris (01/02/06 11:15 PM)


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Barish
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #246599 - 02/02/06 12:00 AM
I'm not agressive at all. I just asked you a question your reply to which answered your last question.

Had you really studied those parts of the calculus and done what I asked, you would have known how it knew the input wasn't simply a 5hz sine-wave.

Steve, you are right. I'm about to slash my wrists here too.


Frank Zappa was right too. There's more stupidity than hydrogen in the universe.


Everybody else is right as well. World is big enough for all of us.


I remember my uncle's theory of life: "If everyone in the society had a masters degree, who would we get to sweep the streets?"


There must be some superstitious people out there so that snake-oil traders can make a living too.

On you go, ladies and gentlemen.

B.


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Steve Ignorant



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #246618 - 02/02/06 12:31 AM
Who would we get to sweep the streets?
The people with masters in street sweeping?

Ive not read all of this post because it is to long.
But please correct me if I am wrong?

The way i see 192kh is like this yall?!

If ur baking a cake and you have some flour that you sive, it will not cause many lumps. If ur sive is in 192kh then when you run it thu your waves R-verb or whatever, it will process it in finer peices and so be a more refind product,I THINK??

If i produced that album i would use the max Sample rate. I dont think there is a concpiracy to fool people, i just think he doesnt see it as relavent?

Ya Raass clot!!

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Paws
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #246623 - 02/02/06 12:38 AM
I thought the purpose of it was to gave me an excuse to get a new soundcard?

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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246627 - 02/02/06 12:42 AM
Quote kris:

I'm talking about low-level signals where you DON'T have a lot of sampling resolution (although this distortion occurs at all bit-depths, it's level is inversely proportional to bit depth).




Er... hoist on your own petard perhaps.

In a correctly dithered quantiation system, there is no quantisation distortion. Only in a crude undithered system is the level of distortion inversely proportional to the bit depth.

The whole point of dithering is to linearise the transfer function, to achieve nominally zero distortion at the expense of a fixed but very small amount of pure noise (whose flavour depends onthe dithering method chosen).

Resolution absolutely does not diminish with amplitude, only the signal to noise ratio. In a correctly dithered system, it is perfectly possible to encode undistorted signals of a smaller amplitude than the smallest quantisation level.

Hugh

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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Lighthouse_Mastering]
      #246639 - 02/02/06 01:08 AM
Quote Lighthouse_Mastering:

Off the top of my head, Burr Brown make a 24bit high sample rate capable multibit DAC, and I know that there are others.




I guess you are thinking of chips like the PCM1704 and others in that family that all use sign and magnitude conversion... but with 16x(44.1) oversampling filters. Okay, so not quite as heavy handed as true delta-sigma... but then no one uses true (single bit) delta-sigma in pro audio applications anyway. Even these 'multibit' converters employ all the same oversampling techniques, digital filters, noise shaping and so on. There really is no getting away from it.

Quote:

I agree that digital is better today than it was 20yrs ago, but just not as good as it could be. Good to see you are an optimist.




Always the optimist! I fear we may be converging on agreement again here, Dave

hugh

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UnderTow
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246643 - 02/02/06 01:17 AM
Below are my views based on my limited knowledge. I don't claim to be an expert on this subject so I might be making some misstakes. Please anyone correct me if I am wrong.

Quote kris:


So, let's say you sample at 10hz and you input a 5hz sine-wave (remember, in this example we're using a 1-bit system).





This is the first error. Nyquist states that you need a sample rate that EXCEEDS twice the highest frequency of the signal you want to sample.

Quote:


Now try a 4hz sine-wave. We have a problem, 101 is a 5hz sine-wave (after reconstruction),





This is the next problem. A sine wave (sine (x)) doesn't just start out of the blue and end abruptly. Imagine a curve (or imaginery sine wave for lack of a better term) that starts at the point in time of the first of the three samples and stops after the third. You would have angles at the beginning and end of the curve where it joins the flat lines on either side. These angles represent frequencies way beyond 5Hz and thus do not fit withing Nyquist's sampling theory.

In other words, you are describing a wave form that is akin to a true square or saw wave that has infinite bandwidth and can not exist in the analogue world. Things that don't exist can't be sampled.

Quote:


If it can only see a 1 followed by a 0, how can it possibly know the input wasn't simply a 5hz sine-wave?





(Ignoring the 5Hz for a sec). Luckily we never have this situation in real life. CD audio has 44100 samples per second. We humans can certainly not recognise the pitch based on a sound that only lasts 1/22050 of a second.

It would sound as a click wich effectively is a sound with alot of high frequency content way beyond the actual frequency of the wave we were sampling. (That is if anyone does 1/22050 second recordings in the first place. So this fits with what I say above about infinite (or at the least extend) bandwidth.

Quote:


Now take a 100hz sampling rate with the same input. 5hz could be 10x1s, followed by 10x0s. 4hz could be 12x1s followed by 13x0s.

Despite the fact that ALL freqencies are below the Nyquist limit in both cases, the higher sampling rate gives us a better approximation of the same source.





As I have explained above, if the wave you describe could be created in real world, it would have frequency content way beyond Nyquist.

Btw Barish, unlike Hugh, with the exception of giving some nice links to documents about sampling theory and alluding to maths, you have explained ABSOLUTELY NOTHING! (I checked every single one of your posts on this thread). You didn't even seem to pick-up on some errors I posted here that obviously were quite a bit beyond the "joining the dots" missunderstanding for which you have no patience.

On the contrary! You have been insulting, denigrating, aggressive and, contrary to what some have posted, totaly lacking patience. So get off of your high horse. You might have knowledge to share but you are certainly not doing it in this thread.

UnderTow
Edited for blatant typos and other 2:30am brain farts

Edited by UnderTow (02/02/06 01:30 AM)


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246644 - 02/02/06 01:19 AM
Quote kris:

by low bit-depths, I'm talking about frequencies that modulate only the last few bits in a digital system (i.e. at a very low level).




If you're going to talk technical, can we keep the terminolgy accurate to avoid further confusion, please. I think you mean you're are talking about signal levels (not frequencies) that modulate the last few bits..

Quote:

For example, there could be frequencies that only modulate the lowest bit (of course there's dither, but I'm not discussing that here).




Er... how can you talk sensibly about the problems of digitisation in modern converter design without taking dither into account? This is ludicrous. It would be like talking about tape recordings without AC bias, and conveniently managing to ignore the fact that it would sound terrible as a result!

Quote:

Now try a 4hz sine-wave. We have a problem, 101 is a 5hz sine-wave (after reconstruction), but 110011 would be a 2.5hz sine-wave. It's therefore IMPOSSIBLE to accurately sample this 4hz sine waves, despite the fact it falls below the nyquist limit.





Oh dear... this is childishly naieve and doing you no favours at all. I strongly suggest you go away and read a few good books on the subject by reputable authors. Dr John Watkinson is as good a place to start as any: The Art of Digital Audio on Focal Press.

Quote:

Now Hugh makes a good point about the reconstruction filter taking care of this, but I'm afraid it's NOT applicable here because the filter doesn't have sufficient input resolution to produce anything like a valid output!! If it can only see a 1 followed by a 0, how can it possibly know the input wasn't simply a 5hz sine-wave?




Because the little digital goblins have told it so. They listen in on what you send in and make the binary magic happen.... Makes about as much sense as the stuff you are spouting!

It is very simple to feed a high frequency, low level tone in a digital converter, and then decode the output and prove that what comes out is the same frequency tone as you sent in, but obviously well down into the noise -- just as you would expect. Try it... you might surprise yourself.

Hugh

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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Dishpan]
      #246647 - 02/02/06 01:25 AM
Quote kris:

Barish yes I've studied calculus, but I really don't see the need for your hostile tone here, I'm not being agressive at all.




I appreciate you lack of hostility here, and I apologise for Barish's tone -- I'm sure it is born out of sheer frustration rather than malice.

Quote:

Anyway, a 1-bit waveform has no slope, it moves instantly from 0 to 1, so why in this case would derivatives help?




You are choosing to ignore the fundamentally crucial role of dither once again, but I agree with you... we have gone as far as humanly possible on this. Let's all go away and make happy music

hugh

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Stevedog



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #246663 - 02/02/06 03:30 AM
Hugh is the new avatar cos you've finally come out of the mic cupboard about being the real Chumley-Walmer??

For those not in the know, what Hugh is trying to say is this..

The dashed clever boffins down at the laboratories have come up with this totally top hole new way of recording things. You talk into here, points at the microphone, and magick little number pixies convert it to a a collection of smaller bits and then recreates it as a big bit again through your speakerphones.

The larger the number of magick number pixies working on the sound the better they can re build it and the more mellifluous it is on the ear.


At present most people can only afford 44 or 96 pixies but we at SoS towers have the services of 192 of the little chappies so they can rebuild the bits far more accurately than 44.

Simple really chaps...

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Dunewar



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #246685 - 02/02/06 08:35 AM
Waw, 192 pixies....and what do you feed them? Be carefull not to feed too much of Babyshamble's music through them, or they will develop a drug habit and start dating Kate Moss, and you don't want her messing up your pixies!!

BTW, I totally stayed out of this thread because it is way over my head, and I admire people like Hugh that know what they are talking about and take the time to explain it. But the Hitler reference by mister Barish was totally uncalled for, no matter how big his knowledge on the subject.

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UnderTow
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #246724 - 02/02/06 10:07 AM

Waow. Rereading what I wrote last night, I see that I didn't state what I was pointing at: Although you only need two sample points to represent any frequency below 1/2 Nyquist, it has to be in a stream of bits longer than just two or three samples. At least that is how I understand it.

UnderTow


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James PerrettModerator



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Re: What is the point in 192kHz? new [Re: Dunewar]
      #246730 - 02/02/06 10:16 AM
Quote Dunewar:

But the Hitler reference by mister Barish was totally uncalled for, no matter how big his knowledge on the subject.




Or was he simply invoking an old Usenet tradition.....?

But I guess that we've all been through thought processes similar to Kris's back in the days when trying to get to grips with the basics of digital audio. Thankfully Hugh still has the patience to expalain how it really works. Maybe there ought to be a digital audio basics page somewhere on the SOS website (if there isn't already) that we can point newcomers to whenever these kinds of discussions arise.

Cheers

James.

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Barish
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Re: What is the point in 192kHz? new [Re: UnderTow]
      #246868 - 02/02/06 02:03 PM
Quote UnderTow:

Btw Barish, unlike Hugh, with the exception of giving some nice links to documents about sampling theory and alluding to maths, you have explained ABSOLUTELY NOTHING! (I checked every single one of your posts on this thread). You didn't even seem to pick-up on some errors I posted here that obviously were quite a bit beyond the "joining the dots" missunderstanding for which you have no patience.

On the contrary! You have been insulting, denigrating, aggressive and, contrary to what some have posted, totaly lacking patience. So get off of your high horse. You might have knowledge to share but you are certainly not doing it in this thread.





Why? Is it because I didn't rephrase here the same concepts someone else had perfectly put in another location, but rather gave the links instead?

If someone doesn't know the fact that mathematical functions can be derived and integrated and what that means in terms of AD/DA Digital Analog conversion shouldn't be so smugly discussing the fine tunings of it in the first place.

And if they don't know what that is then they can open up the book and study it. I spent three years studying that [ ****** ] and it got in my head even years after that what those theorems meant in audio, so I'm not going to try to explain it all in a forum thread which will disappear in the depths of this forum in two weeks.

I've just shown the way. Those who are REALLY interested in designing one, can go and study it.

Suffice to say, to put it in simple words, complex mathematical functions sometimes yield two different y results at some points on the x axis, which is called alias. That's what exactly happens in the DA audio conversion. Increasing the bandwidth does not solve this problem. It is anti-aliasing that sorts out that problem. And the more time that you give the filter to process, the more accurate the filtering is. If you increase the sampling speed to increase bandwidth, you steal from the time anti-aliasing filters could use. That's why unnecessary expansion of bandwidth has a negative impact on the optimum quality an AD/DA convertor can achieve. It actually compromises the accuracy. You may like what sounds through it, but you can't call it more accurate.

In most cases you'll find that other people's silliness makes you sound arrogant. Some people don't know the most crucial concepts and theorems that are used in designing a converter, yet they are trying to establish a logic by themselves to which they expect the converters to operate to. It doesn't work that way.

Can anyone show me a white paper from another manufacturer that claims the contrary of Lavry paper? I haven't seen any yet. If there is one, please let me know.

Thank you.

B.


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Dishpan



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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #246891 - 02/02/06 02:41 PM


Edited by kris (02/02/06 03:21 PM)


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Dishpan



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Re: What is the point in 192kHz? new [Re: Barish]
      #246893 - 02/02/06 02:44 PM
Deleted. I did say I'd try not to participate in this anymore, and I'm sorry my weakness got the better of me!!

Edited by kris (02/02/06 03:22 PM)


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DCompton



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Re: What is the point in 192kHz? new [Re: Barish]
      #246947 - 02/02/06 03:48 PM
Food for thought.

Does High Sampling Frequency Improve Perceptual Time-Axis Resolution of Digital Audio Signal?

http://www.aes.org/e-lib/browse.cfm?elib=7217

Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect

http://jn.physiology.org/cgi/content/full/83/6/3548#B29


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UnderTow
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Re: What is the point in 192kHz? new [Re: Barish]
      #246956 - 02/02/06 04:01 PM
Quote Barish:



Why? Is it because I didn't rephrase here the same concepts someone else had perfectly put in another location, but rather gave the links instead?





There is nothing wrong with you not having enough time or patience to repeat what others have allready clearly explained but there is absolutely no need for rudeness and agression. Just refrain from posting.

Quote:


Suffice to say, to put it in simple words, complex mathematical functions sometimes yield two different y results at some points on the x axis, which is called alias. That's what exactly happens in the DA audio conversion. Increasing the bandwidth does not solve this problem. It is anti-aliasing that sorts out that problem. And the more time that you give the filter to process, the more accurate the filtering is. If you increase the sampling speed to increase bandwidth, you steal from the time anti-aliasing filters could use. That's why unnecessary expansion of bandwidth has a negative impact on the optimum quality an AD/DA convertor can achieve. It actually compromises the accuracy. You may like what sounds through it, but you can't call it more accurate.





Thanks for sharing your insights.

Quote:


In most cases you'll find that other people's silliness makes you sound arrogant.





Usually it is the tone that makes you sound arrogant. Not the content.

Quote:


Can anyone show me a white paper from another manufacturer that claims the contrary of Lavry paper? I haven't seen any yet. If there is one, please let me know.






I don't think there is one. That doesn't mean _too_ much on itself though. That having been said I think that Dan Lavry is correct in as far as my knowledge goes.

UnderTow


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Stoney



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #247001 - 02/02/06 04:57 PM
Sorry, I can't help myself - I have to jump in again..

Barish has at least made some effort here to direct people to the correct information, but if they have chosen to ignore it, or have read it but don't fully understand it, then that's really not his fault is it.

If people then start claiming they know exactly what's going on, yet show in their explanations they clearly don't, you can understand why his tone may have risen *slightly* above y=0....

Unless you're equally qualified to argue the t*ss, you really should avoid doing so.

Edited by Stoney (02/02/06 04:58 PM)


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Marky
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Re: What is the point in 192kHz? new [Re: UnderTow]
      #247007 - 02/02/06 05:02 PM
Quote UnderTow:



I don't think there is one. That doesn't mean _too_ much on itself though. That having been said I think that Dan Lavry is correct in as far as my knowledge goes.

UnderTow




How wonderful of you to validate Dan's work ! I'm sure he'll be overjoyed to know you have given him the nod!

Can we end this thread now?

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Studio Support Gnome
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a minor change in tone. new [Re: Stoney]
      #247009 - 02/02/06 05:09 PM
Hypothetical , humorous conversation thing....

DL. "there's no point in making 192KHz converters.
\
DCS. "Yes there is...."
/
DL. "well you would say that, what with being someone who makes them..... you're obviously biased aren't you? "
/
DCS, " strange we thought the same about your position, what with , being someone who doesn't make them......"
\
PRM. "pair of wannabees".




Kris 1 bit 10Hz converters.

really mate, you are simply not , for a change, right.,

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James PerrettModerator



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Re: What is the point in 192kHz? new [Re: DCompton]
      #247012 - 02/02/06 05:12 PM
Quote DCompton:

Food for thought.

Does High Sampling Frequency Improve Perceptual Time-Axis Resolution of Digital Audio Signal?

http://www.aes.org/e-lib/browse.cfm?elib=7217




As I understand it from reading the abstract, this simply shows that different filters can sound different. Chances are, they would have obtained similar results by using different designs of filters at the same frequency.
Quote DCompton:


Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect

http://jn.physiology.org/cgi/content/full/83/6/3548#B29




This has already been discussed earlier in this thread.

Cheers

James.

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Barish
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Re: What is the point in 192kHz? new [Re: DCompton]
      #247023 - 02/02/06 05:22 PM
Quote DCompton:

Food for thought.

Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect

http://jn.physiology.org/cgi/content/full/83/6/3548#B29




What part of "this has been discredited" don't you get mate? You've been pushing this the second time in this thread, even though it has already been replied to. do we have to go through things over and over again?

And then they accuse me of arrogance.

Quote:

Does High Sampling Frequency Improve Perceptual Time-Axis Resolution of Digital Audio Signal?

http://www.aes.org/e-lib/browse.cfm?elib=7217




I'll check what that is.

B


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artbreak



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #247035 - 02/02/06 05:30 PM
I like you Barish
don´t get me wrong i also like girls

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Kaw-Liga
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It's back to 44100 hz in my case:) new [Re: Richard Steed]
      #247058 - 02/02/06 06:11 PM
Personally, I don't like those frequencies that 96khz gives my recordings. The guitar booms horribly in the low end and my vocalsss beam in the top. I can't eq it until it is right either... there is just too much information. Nearly all my best-sounding recordings, I've found out lately, are done in 24bit/44khz.

Edited by Kaw-Liga (02/02/06 06:37 PM)


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Barish]
      #247156 - 02/02/06 08:39 PM
Quote Barish:

Quote:

Does High Sampling Frequency Improve Perceptual Time-Axis Resolution of Digital Audio Signal?

http://www.aes.org/e-lib/browse.cfm?elib=7217




I'll check what that is.

B




I think Mike Storey at dCS published an AES paper on this topic too, and I recall it seemed to make sense when reading it, but I know John Watkinson (amongst others) spent some time trying to discredit it. Can't remember the details now though. There was a lot of debate inthe pages of Studio Sound magazine in the early-mid part of 1998 too if memory serves. I'll try to dig them out.

Hugh

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Anonymous
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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #247179 - 02/02/06 09:11 PM
M Story: "A Suggested Explanation For (Some Of The) Audible Differences Between High Sample Rate and Conventional Sample Rate Audio Material"

You can find the paper in the Technical Papers section of the dCS website on the link I gave way back up this thread somewhere. It sticks with some simple ideas and avoids going into the maths but it makes some fairly convincing reading as it stands. Obviously though, with this kind of thing, the devil is in the detail and I'd've preferred to have seen his "workings". I took part in some listening tests related to this and another paper on the dCS site and I have to say that whatever the actual maths involved, empirically, it does stack up alongside what was heard.


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Steve Hill
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #247217 - 02/02/06 10:06 PM
Enlightenment strikes!

The point of 192kHz, to answer the original question, is to provoke heated and often incomprehensible debate, thereby diverting attention from music.

Any other function is imaginary.

I rest my case, m'Lud.

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Lighthouse_Mastering



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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #247219 - 02/02/06 10:07 PM
Quote Hugh Robjohns:


I guess you are thinking of chips like the PCM1704 and others in that family that all use sign and magnitude conversion... but with 16x(44.1) oversampling filters. Okay, so not quite as heavy handed as true delta-sigma... but then no one uses true (single bit) delta-sigma in pro audio applications anyway. Even these 'multibit' converters employ all the same oversampling techniques, digital filters, noise shaping and so on. There really is no getting away from it.




Yes, I think you are right, there is no escape. All the current implementations, have everything built into the single chip. This was not the case a few years ago. This has been done in order to reduce costs.

Quote:

Quote:

I agree that digital is better today than it was 20yrs ago, but just not as good as it could be. Good to see you are an optimist.




Always the optimist! I fear we may be converging on agreement again here, Dave

hugh




I too try to be optomistic, but I am also a perfectionist. I really do believe that we have the capability to have much better performance with the current technology.

Cheers Dave

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UnderTow
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Re: a minor change in tone. new [Re: Studio Support Gnome]
      #247239 - 02/02/06 10:27 PM
I know your post was in humour but just one thing:

Quote Max The Mac:


DCS, " strange we thought the same about your position, what with , being someone who doesn't make them......"





The Lavry black actually can run at 192Khz. It just doesn't have anything on the front panel (or marketing) to show that it does.

UnderTow


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Barish
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #247240 - 02/02/06 10:28 PM
Because I'm not an AES member I couldn't access to AES paper for a discounted price and frankly speaking, I didn't want to pay $20 for an article just to prove a point on an internet forum.

But I have read both the abstract at AES website and 0VU's link. The abstract didn't give me any clue about the details of the test (well, obviously, $20 stuck in there to get it) but dCS guy has a case, but even in his diagrams and explanations, as soon as you go over 60kHz sampling rate, the FIR ringing becomes no issue as the ringing is already pushed out of known audible range. So it is already covered by 88.2 kHz sampling rate, never mind 96. For the pychoacoustic effect of the energy above there is still no consensus. One side say they experimented and proved something the other party fails to replicate.

I'm looking forward to reading Hugh's findings from his archive.

B.


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Grimm Reaper Sound
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Some more interesting links new [Re: The_BPP]
      #247241 - 02/02/06 10:29 PM
Musical Instrument spectra:
http://www.cco.caltech.edu/~boyk/spectra/spectra.htm

Coding high quality digital audio:
http://www.meridian-audio.com/ara/coding2.pdf

Both links are fairly informative without all the messy math.

BTW Barish, to truly analyze digital audio, one does not just take derivatives and integrals, one must also do a Fourier transform (more precisely a Discret Fourier Transform) to get out of the time domain into the frequency domain to do proper frequency analysis. So get off your high horse and quit beating up on people and trying to show them off with triple derivatives and triple integrals (most of which are never used in DFT's).


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Barish
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Re: Some more interesting links new [Re: Grimm Reaper Sound]
      #247256 - 02/02/06 10:43 PM
Quote Grimm Reaper Sound:

BTW Barish, to truly analyze digital audio, one does not just take derivatives and integrals, one must also do a Fourier transform (more precisely a Discret Fourier Transform) to get out of the time domain into the frequency domain to do proper frequency analysis. So get off your high horse and quit beating up on people and trying to show them off with triple derivatives and triple integrals (most of which are never used in DFT's).




The Nyquist theorem is reached to and proven through all derivatives and integrals:

http://en.wikipedia.org/wiki/Nyquist-Shannon_sampling_theorem

http://www.digital-recordings.com/publ/pubneq.html

Thank you.

B.


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Brian Moynihan
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Re: Some more interesting links new [Re: Grimm Reaper Sound]
      #247280 - 02/02/06 11:11 PM
Given that a many instruments (or random sounds) have content above 22khz, and that human hearing doesn't "officially" extend to this range, perhaps we should divide everyone involved in this debate into two camps -

a) You are happy with the fact your digital audio system discards that information because ultimately it's not going to be heard by the end listener, and with a quality recording and playback system, the frequencies they *do* hear are properly reproduced.

b) You'd rather that whatever system you used, it should capture all the available information from the source, even though human hearing limits the audible frequencies, and most consumer formats discard them anyway.

which one are you?

which leads me to my next question....
What's the point of 96khz?

sorry....
Bob


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ghellquist



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #247302 - 02/02/06 11:48 PM
First a word to Hugh -- you are great in not losing your temper and continuing to try to convince. Please keep it up.

Just to give discussion even a bit more fuel, here is a rather nice page on the subject matter:
http://en.wikipedia.org/wiki/Nyquist-Shannon_sampling_theorem

What you might notice is that there is a difference between a continous signal (say a sustained note) and a changing signal (say the attack of a drum hit). The simplified methods work for continuos signals, but you need a bit more advanced mathematics to handle changing signals. Rest assured though that they totally agree and the results are the same as far as the mathematics goes. If you want to do the "connect-the-dots" exercise, please at least use sinc-functions.

In the real world you have to conted with reality, and then things seldom are quite as easy. I still think that ears are made for listening though, so go on and listen. If you happen to hear a difference between sampling at 44.1 and 192 it is NOT because of Nyquist sampling theorem (which proves that there is no hearable difference), but because of the practical imperfections of real-world equipment.

And in the real world, different converters behave differently. My converters might actually sound best at 44.1, yours at 192, who knows?

Gunnar


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Marky
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Re: Some more interesting links new [Re: Grimm Reaper Sound]
      #247309 - 03/02/06 12:19 AM
Quote Grimm Reaper Sound:



BTW Barish, to truly analyze digital audio, one does not just take derivatives and integrals, one must also do a Fourier transform (more precisely a Discret Fourier Transform) to get out of the time domain into the frequency domain to do proper frequency analysis. So get off your high horse and quit beating up on people and trying to show them off with triple derivatives and triple integrals (most of which are never used in DFT's).




The *triple* derivatives and integrals certainly had me confused (and I'm an engineer in a DSP company, so I should know, or something )... but fundamental Fourier math does involve the common occurance of integrals.

The continuous-Fast Fourier Transform for e.g. is a single integral of a product (multiplied by 1/2pi). Fundamentally though, DFT which you mentioned, is just a sum-of-products.


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DCompton



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Re: Some more interesting links new [Re: Barish]
      #247313 - 03/02/06 12:30 AM
Barish the point of these articles was not to prove you wrong or other wise but simply present another point of view on the subject.
nothing else

Cheers


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Barish
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Re: Some more interesting links new [Re: Marky]
      #247319 - 03/02/06 12:48 AM
Quote Marky:

The *triple* derivatives and integrals certainly had me confused (and I'm an engineer in a DSP company, so I should know, or something )... but fundamental Fourier math does involve the common occurance of integrals.





My point was to point out that you can derive a high level function a couple of steps down, and then integrate them to reach to the original function healthily, just to support the fact that sound waves can be similarly restored from digital form with no loss by a similar integration. But you are right, I should have made it more clear in my phrasing.

Thanks for pointing out.

B.


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Barish
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Re: Some more interesting links new [Re: DCompton]
      #247320 - 03/02/06 12:49 AM
Quote DCompton:

Barish the point of these articles was not to prove you wrong or other wise but simply present another point of view on the subject.
nothing else

Cheers




Agreed.

B.


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Dunewar



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #247471 - 03/02/06 11:06 AM
The maths involved here are way over my head, and I respect everyone that has a far better knowledge of them than I do.
But I have a practical question. Since none of us can listen to 0's and 1's directly, or to voltages, we all need monitors to translate that stream of signals into moving air.
I'm no expert on the thing, but what is the upper limit of a monitor's frequency response? Surely, any sound above that is not present on its output, and can't influence the signal (acoustical or psycho-acoustical or whatever).

Might this just be a case of 'a chain is as strong as its weakest link'? I don't understand the need for DA converters that give you pristine signals up to 96khz (192/2) if your monitors can't translate that into real sound.

Of course, I am making major abstractions of any advantages on the AD side (do microphones record that high?), and of any other technical advantages that may or may not be present.

And by all means, feel free to slaughter me on account of my humble knowledge

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Miles Davis


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Dunewar]
      #247609 - 03/02/06 01:54 PM
Quote Dunewar:

I'm no expert on the thing, but what is the upper limit of a monitor's frequency response?




Most speakers are falling off pretty steeply above about 22kHz, but some now have 'supertweeters' which claim to extend the output to 40kHz or thereabouts (Tannoy are a big fan of this approach, for example).

Quote:

Surely, any sound above that is not present on its output, and can't influence the signal (acoustical or psycho-acoustical or whatever).




Any energy fed into a transducer will cause some effect, even if it is only local heating -- but these effects can have secondary effects on more audible parts of the frequency range. Beats and intermodulations, for example. Also, ultrasonic signals can cause intermodulation and non-linaarity issues with some electronics, again resulting in audible side effects. None of this is ever entirely straightforward because of the real world issues of practical implementations.

Quote:

Might this just be a case of 'a chain is as strong as its weakest link'?





Absolutely, yes. Which is why I alsways argue that the first need is to sort out the room, and then to buy the best monitors you can afford. Most people choose to ignore the room and buy the cheapest monitors they can, and spend all their money on flash computers and boxes with flashing lights instead! Even though they won't be able to hear the differences.

Quote:

I don't understand the need for DA converters that give you pristine signals up to 96khz (192/2) if your monitors can't translate that into real sound.




I agree, there is little point if that is the benefit. I don't think it is, though. There are obvious technical benefits from using a higher sample rate for acquisition and post-production, even if the final output is destined for 44.1. These include more accurate EQ curves, more accurate metering, and more accurate dynamic control. There is also the obvious benefit of being able to accommodate less than perfect anti-alias and reconstruction filters without impinging the audible frequency range. The down side is more data storage, higher straing on DSP processess, and the need for far more stringent clocking regimes. ON the whole, though, I think the advantages outweigh the disadvantages. Moving up to 192 or 384, to my mind, introduces more disadvantages with the current level of technology, and offers no further advantages at all.

Quote:

Of course, I am making major abstractions of any advantages on the AD side (do microphones record that high?), and of any other technical advantages that may or may not be present.




Very few mics have a response that remains anything like flat above 16kHz. Most are already begining to fall gy then. The better small diaphgram mics will be flat to 20kHz or thereabouts, and then fall fairly quickly again. A very few have been specially designed to extend flatish to 30 or 40kHz, but there are significant side effects in pushing transducers to do that -- mainly involving higher broadband noise and distortion artefacts.

hugh

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Dunewar



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Re: What is the point in 192kHz? new [Re: The_BPP]
      #247617 - 03/02/06 02:13 PM
Quote:

Any energy fed into a transducer will cause some effect, even if it is only local heating -- but these effects can have secondary effects on more audible parts of the frequency range. Beats and intermodulations, for example. Also, ultrasonic signals can cause intermodulation and non-linaarity issues with some electronics, again resulting in audible side effects. None of this is ever entirely straightforward because of the real world issues of practical implementations.



Aha, there's the flaw in my reasoning. Thanx Hugh, now it makes sense. I thought that effects like beats and intermodulations took place in the airwaves of sound, but now I understand that it happens in the electronics before the tweeters start flapping about...

But the "weakest link" approach is (according to me) the best approach, and is an approach that makes perfectly clear why sample rates like 192 khz and beyond are useless for people like me. My room is far from perfect, my monitors are cheap, and my recording methods are far from ideal. So moving my converters up to 192khz would be like putting a porsche engine into a volkswagen... So for me this is a theoretical problem, i've got bigger problems to sort out in my recording chain before that. And I bet it is for a lot of people.

Of course, when you are talking about high-class recording facilities, with excellent sounding rooms and 10K+ microphones, then i'll shut up, because I don't know squad about that. That's like a hobbiest car-fixer telling a formula 1 engineer what to do.........

--------------------
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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Barish]
      #247618 - 03/02/06 02:14 PM
Quote Barish:

I'm looking forward to reading Hugh's findings from his archive.




Had a quick rummage through the archives. Studio Sound 1998. Feb edition, John Watkinson argued against the need for sampling at 96kHz and above on the basis that theory says you don't need to. Any apparent sonic differences must be because the 48kHz designs are imperfect.

April Edition, Mike Story write about the perceived benefits of 96kHz in relation to greater spatial accuracy because of improved filter responses (shorter impulses).

June edition, John Watkinson defends his corner in typical fashion. He suggests that the dCS experiments were flawed because they contain no proof that only the sample rate changed between tests -- suggesting that other (presumably filter-related) aspects may have changed too.

He goes on to argue that the dCS arguments rely on the assumption of linear phase filters, but that any practical decimation filter implementation involving noise shaping will inherently involve recursion which is not necessarily phase linear.

He suggests that the resulting group delays from non phase linear filters may indeed be audible, and that a doubling of sample rate would halve this group delay, which would certainly be an audible change. He therefore claims that in switching from 48 to 96kHz, the test listeners were simply detecting the improved phase linearity in the audio band. This would certainly have the effect of improving the spatial resolution noted in the dCS experiments, but not for the reasons Mike Story claimed.

He went on to ask for measurements of the phase linearity of the dCS converters at 48 and 96kHZ to see if it changed. As far as I can see, no response was ever provided to that challenge.

In the August edition another writer claimed that perhaps the audible benefit of 96kHz (and higher) was because of the inherently much shorter filter impulse responses.

He claimed that the ear can react to the ultrasonic pre-ringing of linear phase filters. Pre-ringing is something we never hear from analogue filters, or in normal real life, of course.

Higher sampling rates reduced the period of pre-ringing, and it was argued stimulates the ear less. He also suggests that filter designs that don't have pre-ringing characteristics (i.e more like traditional analogue filters) would sound better -- and this is something dCS also claims.

It's all a minefield, and it's all been debated at length before by people with far better brains than any of us!

Hugh

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Barish
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #247654 - 03/02/06 03:02 PM
Yes, this is very much like arguing over which religion is better. No one wins and the life goes on.

Thanks for summing this up with a fashionly manner, Hugh. I hope we all got something out of this. I for one realized after all this debate that I don't need 192kHz converters, but I think I could use a bit of those anger management courses.

Regards,

B.


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coool



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Re: What is the point in 192kHz? new [Re: Hugh Robjohns]
      #247786 - 03/02/06 06:36 PM
when i listen to cd tracks copied into my computer, even though winamp plays em at 16/44 it still sounds much better through my 24/96 soundcard than the original on a decent cd player. i presume a 24/192 soundcard would have to be twice as accurate and would sound even better for it .. i dont get the maths and i dont believe in pixies, but i liked the flour and sieve analogy best

grainger


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ghellquist



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Re: What is the point in 192kHz? new [Re: coool]
      #247889 - 03/02/06 09:12 PM
Quote grAInger:

when i listen to cd tracks copied into my computer, even though winamp plays em at 16/44 it still sounds much better through my 24/96 soundcard than the original on a decent cd player. i presume a 24/192 soundcard would have to be twice as accurate and would sound even better for it .. i dont get the maths and i dont believe in pixies, but i liked the flour and sieve analogy best

grainger




What yuo are listening to is NOT 96kHz signals, what you hear is a 44.1 signal (maybe processed in various ways). The reason you like it better is probably that the analog parts of the card are better than the stuff in your CD player. There is absolutely nothing saying that a card that supports 192 will have better circuits or sound better. Actually I believe that you often swap the 192 support for lower quality in the rest of the circuit if you buy project studio equipment today.

Gunnar


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Grimm Reaper Sound
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Re: Some more interesting links new [Re: Barish]
      #248032 - 04/02/06 10:12 AM
Quote Barish:

Quote Grimm Reaper Sound:

BTW Barish, to truly analyze digital audio, one does not just take derivatives and integrals, one must also do a Fourier transform (more precisely a Discret Fourier Transform) to get out of the time domain into the frequency domain to do proper frequency analysis. So get off your high horse and quit beating up on people and trying to show them off with triple derivatives and triple integrals (most of which are never used in DFT's).




The Nyquist theorem is reached to and proven through all derivatives and integrals:

http://en.wikipedia.org/wiki/Nyquist-Shannon_sampling_theorem

http://www.digital-recordings.com/publ/pubneq.html

Thank you.

B.




Euh Barish, that's a single integral there not a triple...
Which was my point, don't confuse people with triple integrals when you only need a single to get a DFT done.
And don't bother sending links to Wikipedia, I get a much more detailed analysis in my engineering texts.


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Grimm Reaper Sound
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Re: What is the point in 192kHz? new [Re: The_BPP]
      #248092 - 04/02/06 01:36 PM
Let's recenter the discussion for 196k.
In summary so far (and Hugh stated this a few pages back)
in theory we would only need 40kHz sampling.

Almost everybody agrees that 96kHz is better sounding.

Most electronics designers agree that 96Khz will do the job but it is a bit of overkill (approx 60Khz being needed with proper dithering and noise shapping).

Outboard equipment (I refer here to mics, amps, monitors, etc) are limited in bandwidth to 20-25K so in theory they should not need anything over 96K.

High end analog could capture 100K, but the associated outboard gear is limited.

Musical instruments can and do go to much higher frequencies
http://www.cco.caltech.edu/~boyk/spectra/spectra.htm

So, based on these statements (verify the validities on your own) the question becomes:
Is 196K truly needed?


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Hugh RobjohnsAdministrator
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Re: What is the point in 192kHz? new [Re: Grimm Reaper Sound]
      #248137 - 04/02/06 04:36 PM
The rate is 192kHz, not 196 -- just to make a small pedantic point.

Some musical instruments do generate ultrasonic harmonics and/or noise -- but that doesn't mean or imply that such components are relevant to our perception or appreciation of their sound characteristics, and I know of no scientific tests to establish this issue one way or the other. The ultrasonic componetns certainly contribute no pitch information -- tests have definitely proved that point. So I think this element of your argument is irrelevant and potentially misleading.

Not all outboard equipment is restricted to a 20kHz top end -- some is deliberately designed to extend to 100kHz or so -- but even those that have a nominal 20kHz bandwidth will certainly have a far more gentle roll off at the high end than a 44.1 or 48kHz digital system. That seems to me another good argument in favour of 96kHz systems.

However, the issue is really one of theory versus practicality, with the laws of diminishing returns thrown in.

Theory suggests 48kHz should be adequate, 60kHz would be ideal. Despite lots of misguided arguments, the theory has never been invalidated, ever.

96kHz is probably the best current compromise, sounding better than poorly engineered 48kHz systems, but not because the higher sampling rate is actually required -- it's because the practical design constraints of working at 96 have a negligable impact on the perceived sound quality.

There are also technical benefits which could be achieved in better engineered 48kHz systems, but they more or less happen for free in 96kHz systems.

192 and 384 build on the benefits of 96kHz, in terms of even more relaxed filtering constraints, less draconian noise-shaping and even shorter filter impulse responses... but place ludicrous (and probably unworkable) tolerances on clock accuracy, as well as silly demands on data storage and DSP overheads.

The bottom line, though, is if you like chasing numbers, have the budgets, and believe it sounds better, go with 192 or 384. No one's going to stop you. if you really want to, you can even release your material on DVD-A in native 24bit/192kHz PCm. Or transcode to DSD and release as an SACD. Hell, why not go the whole hog and sample at 2.8224MHz in native DSD

For those whose feet still reach the ground, 96kHz is probably the most cost-effective format, even for budget applications. But there still isn't much wrong with 44.1 and 48kHz systems for most people, most of the time, especially if you choose the equipment carefully!

After six pages of this I'm getting bored now... shall we move on to something more interesting... pretty please

Hugh


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Stan



Joined: 17/01/05
Posts: 1311
Loc: Big Rock Candy Mountain
Re: What is the point in 192kHz? new [Re: ]
      #248160 - 04/02/06 05:34 PM
Quote 0VU:

M Story: "A Suggested Explanation For (Some Of The) Audible Differences Between High Sample Rate and Conventional Sample Rate Audio Material"

You can find the paper in the Technical Papers section of the dCS website on the link I gave way back up this thread somewhere. It sticks with some simple ideas and avoids going into the maths but it makes some fairly convincing reading as it stands. Obviously though, with this kind of thing, the devil is in the detail and I'd've preferred to have seen his "workings". I took part in some listening tests related to this and another paper on the dCS site and I have to say that whatever the actual maths involved, empirically, it does stack up alongside what was heard.




Just what I needed. Thanks for the link OVU.

--------------------
.. is this thing on?


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Shahi



Joined: 10/10/06
Posts: 4
Re: What is the point in 192kHz? new [Re: The_BPP]
      #365677 - 11/10/06 02:37 AM
Thank you all for your time & replies, your comments have been really helpful for me.

All the best.

Shahi


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