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A-D & D-A converters, budget vs high-end

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Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 3:19 pm
by Hugh Robjohns
Equipment testing is a fascinating subject. We can certainly measure a lot of things that we can't ~apparently~ hear, and there may well be some things that we can hear but can't measure (reliably).

The well known pro-audio author Dr John Watkinson has suggested that, as the more advanced lossy data-codecs are based around a model of human hearing, they could actually form the basis of a more accurate means of assessing the quality/accuracy of audio equipment, sine they could reflect the things that we actually hear. I believe he was specifically considering loudspeakers when he made this suggestion.

The idea would be to play a very high quality source recording through a lossy codec, and to reduce the coding bit rate step by step until artefacts became audible. The better the loudspeaker (or other equipment), the sooner the artefacts would be revealed... and vice versa.

As for the lost of converters in your link, I usually mention them in my reviews because I get asked to when I meet people at trade shows etc -- just as I'm asked for photos of the insides of the products. And these things can be revealing and informative.

For example, knowing which converter chips has been used gives an indication of the cost -- and therefore quality -- of components used, and if a manufacturer is only prepared to employ a low-cost converter they've probably used low cost/quality components elsewhere too.

Moreover, if the specific converter chip manufacturer claims it has, say, a 118dB dynamic range but the equipment only measures with a 112dB range, that suggests the design/build is compromised in some way as the performance of the converter is not being realised. So what else hasn't been designed very well (it's usually the power supply or the clocking... :-) )

H

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 3:37 pm
by Ariosto
blinddrew wrote:I'm just wondering how long it takes to back up a reasonable sized project to the cloud at that kind of sample rate? Especially if you're doing the whole project not just mixes and stems.

It does take a long time. Uploading is so slow in comparison to downloading. I have 80-100 MBPS download but only 6MBPS upload. For this reason I never upload complete projects as these are often 1, 2 or 3+ Gigabytes. So I only upload the rendered .wav files but these can be well in excess of 500GB each at 96K sample rate. Two or three files and it amounts to best part of an hour to upload.

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 3:46 pm
by Hugh Robjohns
Ariosto wrote:Uploading is so slow in comparison to downloading. I have 80-100 MBPS download but only 6MBPS upload.

If you want faster uploads just talk to your broadband supplier and I'm sure they could assist for a small increase in your monthly fee.... I have 66Mbps down and 18Mbps up here.

H

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 4:30 pm
by ef37a
Hugh Robjohns wrote:
Ariosto wrote:Uploading is so slow in comparison to downloading. I have 80-100 MBPS download but only 6MBPS upload.

If you want faster uploads just talk to your broadband supplier and I'm sure they could assist for a small increase in your monthly fee.... I have 66Mbps down and 18Mbps up here.

H

My download is 20-24M wifi (laptop 1mtr from router) but is 37M on copper. The upload is a very consistent 9M wifi or copper, anyone know why?

I am with Talk Talk who are ******es to deal with but in over 4 years I have have virtually no breaks in service or slow downs.

I am FTTC and the cab is but 50mtrs down the frog. My 9M upload is ten times better than it was on direct landline. Perhaps you would have to go fibre to client to better 9M?

BTW, serves me right trying to be a smart****! I was meaning the petabytes of data the astrophycisists handle!

Dave.

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 4:50 pm
by Aural Reject
Standard fibre used to be “40/10” so max 40 down and 10 up. The ‘super fast” stuff was sold at 80/20.

The download speed is amongst other things down to the distance between the cabinet and the router and the quality of the cabling and connections.

The upload is usually tweakable server side and is limited by the ISP so I’d imagine the 9 up is easily achievable by wired and wireless methods (download over WiFi is usually slower than it is over cable).

I’ve got Virgin 350 here....and I actually get 320 ish down over WiFi, 360 cabled and about 26 up over both. It ain’t that cheap though.

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 4:57 pm
by Hugh Robjohns
ef37a wrote:My download is 20-24M wifi (laptop 1mtr from router) but is 37M on copper. The upload is a very consistent 9M wifi or copper, anyone know why?

If you're asking why the wifi link is slower than a cabled connection, it's because it's wireless! ;-) It's quite normal for a wired connection to be faster than wifi -- although the differences are getting smaller with the latest high-speed connection standards.

There are lots of factors affecting wifi speed. Firstly, there's the specific connection standard your laptop and router are using (802.11b, 802.11g, 802.11n, 802.11ac.. etc). In general, the older standards are slower. Then there's the router channel and frequency you're using and whether neighbours are sharing the same channel(s) -- interference will slow things down dramatically. And then there's the distance between laptop and wifi router and the number of other devices sitting on your wifi channel at the same time... More of both being slower, of course.

If you have a smart phone you can download various apps that indicate the local channel occupation and signal strengths, which can be very helpful in optimising your wifi channel selection and router placement.

Perhaps you would have to go fibre to client to better 9M?

No. I'm, FTTC as well and I have double that upload speed... (and the cabinet is further away than yours). I suspect the 9Mbps limit is imposed by the provider to manage data bandwidths, rather than being a physical or hardware limitation.

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 6:15 pm
by ef37a
Hugh, sorry I asked wrongly. It is the consistent 9M (9.2 as a rule) that I was boggled by. I can see wif fi being slower than copper.

The laptop is a rather elderly HP i3 g6 and perhaps a better USB network dongle would help? Not that I am all that bothered, 22M is plenty good enough for my needs and the 9M up a great boon.
I shall have a much later W10 laptop by Christmas anyway, might be faster?

Dave.

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 6:22 pm
by Hugh Robjohns
ef37a wrote:Hugh, sorry I asked wrongly. It is the consistent 9M (9.2 as a rule) that I was boggled by.

Ah... well that's just a network management thing -- an arbitrary soft limit imposed by the network providers to manage data throughput.

H

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 7:57 pm
by Tim Gillett
Jack Ruston wrote:
Tim Gillett wrote:
Jack Ruston wrote:
hobbyist wrote:How do you measure how 'quality' <<improves (y)our work>> when the vast majority of consumers cant tell and dont care ?

I don't know how many more ways I can say it...The conversion changes the decisions I make - The eq points are different, the compression time constants, reverbs etc. The balance changes. Hugh has explained this too.
Jack, there must be reasons why the different converter changes the eq points, compression time constants, reverbs etc. What would they be? How does it relate to the performance specs of the respective converters?

That's the big question. I don't know. And I don't know if they know, but that they just can't do it at the price point, or if they don't know, and just continue to champion frequency response at 20k, and noise floor, as a way of saying 'look, it's perfect'.

For me that different high end converters would audibly change the eq points or compression time constants or reverb seems highly unlikely. And if there were audible changes I wouldnt expect them to be described in those ways. Hugh what's your take on Jack's claims?

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 8:10 pm
by Jack Ruston
Oh yeah, now I come to think of it, you're absolutely right. Thank goodness you were here to help me see how wrong I've been. :)

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 8:50 pm
by James Perrett
Tim Gillett wrote:
For me that different high end converters would audibly change the eq points or compression time constants or reverb seems highly unlikely.

Tim - I think you've misunderstood what Jack is saying. His choice of reverb, eq or compression parameters would be affected by the characteristics of the convertor. He's not saying that the convertor would appear to change these parameters themselves. Now I don't know which particular convertors Jack has experienced this with but I can certainly believe that small changes in something like jitter characteristics or filtering could cause this.

The biggest problem in convincing the sceptics is the need for extremely good monitoring to hear these changes reliably. If you don't have good monitoring then I can quite understand you wondering what all the fuss is about.

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 8:53 pm
by Hugh Robjohns
Tim Gillett wrote:Hugh what's your take on Jack's claims?

My take is that I'd be wasting my time writing this reply... But here goes anyway...

It seems to me completely illogical for anyone without relevant experience to doubt those who do. Anyway, I've already described the benefits I associate with high-end gear, which are very similar to those Jack has described.

It's just like the aural equivalent of looking through a cleaner window -- you can see/hear things a little more clearly, and that makes it easier to make decisions about what processing is needed, and to apply it more delicately.

These are very small benefits, for sure, but when you're doing this stuff all day everyday, it's noticeable and it makes a real difference to the way you work... including having more finesse in the choices of things like dynamic time constants, EQ bandwidths and gains, reverb parameters and so on. And yes, many experienced clients notice and appreciate it too.

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 9:21 pm
by hobbyist
Hugh Robjohns wrote:
Tim Gillett wrote:Hugh what's your take on Jack's claims?

My take is that I'd be wasting my time writing this reply... But here goes anyway...

It seems to me completely illogical for anyone without relevant experience to doubt those who do. Anyway, I've already described the benefits I associate with high-end gear, which are very similar to those Jack has described.

It's just like the aural equivalent of looking through a cleaner window -- you can see/hear things a little more clearly, and that makes it easier to make decisions about what processing is needed, and to apply it more delicately.

These are very small benefits, for sure, but when you're doing this stuff all day everyday, it's noticeable and it makes a real difference to the way you work... including having more finesse in the choices of things like dynamic time constants, EQ bandwidths and gains, reverb parameters and so on. And yes, many experienced clients notice and appreciate it too.

And that would be a logical fallacy called appeal to authority.

No one disputes it makes a difference. Only that you can not say one pane of glass is better than another when you come to the higher half of all glass panes.

Re: A-D & D-A converters, budget vs high-end

PostPosted: Wed Aug 21, 2019 10:12 pm
by Logarhythm
hobbyist wrote:No one disputes it makes a difference. Only that you can not say one pane of glass is better than another when you come to the higher half of all glass panes.
Um, I think you probably can. Indeed it is probably actually much easier to compare panes of glass than a/d converters, considering solely the property of transparency that Hugh mentioned - simply point a monochromatic beam at it, sweep across wavelengths of 400-800nm, and the "best" glass is surely the one for which the absorption value integrated across the measured range is lowest.
And yes, as someone who spent more hours than I care to remember locked in a very dark room taking optical measurements of various nanoscale structures constructed on glass slides, I can assure you that there are applications for which this genuinely does make a difference. Admittedly probably not for the average domestic double glazing, but then this is all becoming curiously analogous to the difference between the a/d requirements of a top end studio and engineer, as compared to those of amateurs like me ;)

Re: A-D & D-A converters, budget vs high-end

PostPosted: Thu Aug 22, 2019 12:53 am
by hobbyist
Logarhythm wrote:
hobbyist wrote:No one disputes it makes a difference. Only that you can not say one pane of glass is better than another when you come to the higher half of all glass panes.
Um, I think you probably can. Indeed it is probably actually much easier to compare panes of glass than a/d converters, considering solely the property of transparency that Hugh mentioned - simply point a monochromatic beam at it, sweep across wavelengths of 400-800nm, and the "best" glass is surely the one for which the absorption value integrated across the measured range is lowest.
And yes, as someone who spent more hours than I care to remember locked in a very dark room taking optical measurements of various nanoscale structures constructed on glass slides, I can assure you that there are applications for which this genuinely does make a difference. Admittedly probably not for the average domestic double glazing, but then this is all becoming curiously analogous to the difference between the a/d requirements of a top end studio and engineer, as compared to those of amateurs like me ;)

There are many other parameters to consider and that would say you cannot logically say which is best.

Your surely best is your opinion. I might prefer some uv filtering,
others may care about strength against breaking, and if your application makes a difference then that would make your choice different but not prove that any pane was THE best.