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What's the most time-consuming part of your post workflow?

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Re: What's the most time-consuming part of your post workflow?

Postby Moroccomoose » Tue Feb 11, 2020 6:03 pm

Hi guys, sorry, I think I'm missing something here...This talk of manually reducing peaks and Gclip. Why is this different to just using a compressor?

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Re: What's the most time-consuming part of your post workflow?

Postby Hugh Robjohns » Tue Feb 11, 2020 7:18 pm

Most compressors react after the event, (the attack time deliberately slugs their ability to capture the initial transient), so won't actually catch the fastest, briefest transients. A dedicated limiter usually has a much faster attack time, so will do a better job of catching and reducing transients, but it still won't get them all.

Some limiters (and compressors, actually) have a 'look-ahead' ability to they can anticipate the transient's arrival and dip the gain slightly in advance. In analogue days, broadcast limiters achieved this with an analogue delay line, made up from lots of coils of wire and a train of capacitors, which delayed the audio signal by a few hundred microseconds while the side-chain monitored the signal before the delay line so that the gain-reduction was applied fractionally before it was needed. In the digital DAW world, that kind of look-ahead is almost trivial to achieve by comparison as it just requires a slightly advanced read of data from the hard drive.

But a simpler approach is simply to deliberately clip the top off the fastest, biggest transients. It was actually quite commonly done in analogue days and it works because if the transient is short enough our ears just don't respond to the clipping distortion (and the resulting distortion products are naturally at higher frequencies than the transient's fundamental because they are odd-order harmonics.

Unfortunately, that idea doesn't work quite as well in the digital world for the reasons I explained earlier: the resulting distortion products are created inside the digital domain and extend beyond half the sample rate... which is an 'illegal condition'. This creates aliasing distortion where the distortion products get folded back into the audio band at non-musically-related frequencies, some of which will be below the original fundamental... and our ears can pick up on that remarkably well because it is a completely unnatural thing and so very obvious.

Of course, there are ways around the problem, but they involve extra complications such as oversampling and more linear-phase digital filtering as a part of the process which can become processor-intensive.

This is why many mastering engineers, if they want to intentionally clip transient peaks as part of their attempts to make a track louder than everyone else's, often choose to clip in the analogue domain by running the mix out of the computer, through a D-A and back in through an A-D via a preamp or other analogue box to perform the actual clipping (if clipping the actual A-D isn't deemed satisfactory for some reason).
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Re: What's the most time-consuming part of your post workflow?

Postby Folderol » Tue Feb 11, 2020 11:32 pm

I'm actually surprised this is still done. Even Audacity has a pretty good fast lookahead limiter. Personally I've never needed to change it's default settings, and I've used it a fair bit over the years.
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Re: What's the most time-consuming part of your post workflow?

Postby Eddy Deegan » Wed Feb 12, 2020 12:22 am

Hugh Robjohns wrote:In the digital DAW world, that kind of look-ahead is almost trivial to achieve by comparison as it just requires a slightly advanced read of data from the hard drive.

This intrigued me. I'm awaiting delivery of a book that will (I hope) provide me with enough information to step fully into the world of writing my own plugins in C/C++ as I want to resurrect an idea I had way back in the Atari days. To be accurate, my desired project is MIDI related but I'm still intrigued!

Given that the API between the host and the plugin is (for the most part) the whole world as far as the plugin is concerned (barring random stuff like file and network access for its own stuff) I was curious as to how a plugin can 'look ahead' in a data stream that the host is responsible for giving it.

I don't know the answer (and I'm not expecting anyone else to particularly, but if anyone does I would love to know) but as far as I can tell from some basic searches there is a setInitialDelay() function that plugins can invoke to delay their output, thus allowing an internal buffer to be built and which can be interrogated/analysed any way the plugin desires.

I am having trouble understanding how a plugin can read ahead on the hard drive as it's got no way that I can find so far of knowing where on the hard drive (which files and which offsets in them) to look.

That said, I'm in the early stages of looking into this stuff myself so I only going on what I know.

Invoking the setInitialDelay() function would increase the latency by the length of the buffer unless I've misunderstood something. Maybe that's the way it works; a few hundred microseconds is sub-millisecond and as such has little effect on overall latency unless multiple plugins are chained in a channel strip.

Not a question as such, just thinking aloud as the subject resonated with me :-)

If anyone knows more about this stuff or can put me in touch with someone who does I would be very grateful, though I suspect it's a bit unlikely. I'm hoping the book I ordered will provide everything I need to know. I have some quite serious plans to create a MIDI plugin which I want to exist, which could be attractive to others and there is less information online for developers than there is for most 'conventional' programming.

Others have done it so I know it to be possible but every little helps!
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Re: What's the most time-consuming part of your post workflow?

Postby desmond » Wed Feb 12, 2020 12:28 am

Yes, that's more or less how it works - you get a buffer of audio data, and you can let the host know your latency so you can work on the audio stream in the way that's most convenient.

The host will compensate for your plugin's latency where it can (ie except in real time).
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Re: What's the most time-consuming part of your post workflow?

Postby Eddy Deegan » Wed Feb 12, 2020 12:34 am

That makes sense - thanks :thumbup:
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Re: What's the most time-consuming part of your post workflow?

Postby Agharta » Wed Feb 12, 2020 1:25 am

Eddy, whats the name of that book?
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Re: What's the most time-consuming part of your post workflow?

Postby Martin Walker » Wed Feb 12, 2020 1:44 am

The Elf wrote:If I could hear GClip working I would consider I'm overusing it - if it clips more than one or two samples over a twenty second window I'm backing it off!

Ah, that rather explains why I abandoned GClip - to push the peak level on this other plug-in to -2dBFS but no higher - I chopped off the acoustic string bass transient completely, so was using it rather more aggressively.

I came up with a scheme using several Reaper bundled plug-ins so I could audition just the audio part that was being removed (very useful in various other scenarios!) , which allowed me to remove the transient completely without any of the main body of the sound. It was perfect for achieving maximum level, but did compromise the string bass sound to some extent.


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Re: What's the most time-consuming part of your post workflow?

Postby Eddy Deegan » Wed Feb 12, 2020 2:12 am

Agharta wrote:Eddy, whats the name of that book?

"Designing Audio Effect Plugins in C++" by Will Pirkle. It doesn't specifically reference MIDI in the title but I'm hopeful it'll give me enough to get going and it'll certainly fill in a lot of the background. Although my primary focus is MIDI at present I'm interested in the potential of coding up some audio related stuff in due course also, if only for my own experimental quirky plugins.

I'm completely comfortable with C and 'ok' at C++ but brushing up the C++ chops seems quite fun, not to mention useful, and of course you can link C binaries from C++ wrappers and vice versa so all in all it seems a good place to start.

https://smile.amazon.co.uk/Designing-Au ... 1138591939

Designing Audio Effect Plugins in C++ presents everything you need to know about digital signal processing in an accessible way. Not just another theory-heavy digital signal processing book, nor another dull build-a-generic-database programming book, this book includes fully worked, downloadable code for dozens of professional audio effect plugins and practically presented algorithms.

Sections include the basics of audio signal processing, the anatomy of a plugin, AAX, AU and VST3 programming guides; implementation details; and actual projects and code. More than 50 fully coded C++ audio signal-processing objects are included. Start with an intuitive and practical introduction to the digital signal processing (DSP) theory behind audio plug-ins, and quickly move on to plugin implementation, gain knowledge of algorithms on classical, virtual analog, and wave digital filters, delay, reverb, modulated effects, dynamics processing, pitch shifting, nonlinear processing, sample rate conversion and more. You will then be ready to design and implement your own unique plugins on any platform and within almost any host program.

This new edition is fully updated and improved and presents a plugin core that allows readers to move freely between application programming interfaces and platforms. Readers are expected to have some knowledge of C++ and high school math.

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Re: What's the most time-consuming part of your post workflow?

Postby desmond » Wed Feb 12, 2020 2:36 am

I strongly recommend using Juce as a plugin development framework, so you don't have to worry about all the tedious things about making plugins, and can just focus your effort on the processing and the interface - plus it has many useful audio/MIDI-related features built-in... :thumbup:
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Re: What's the most time-consuming part of your post workflow?

Postby Eddy Deegan » Wed Feb 12, 2020 9:18 am

desmond wrote:I strongly recommend using Juce as a plugin development framework, so you don't have to worry about all the tedious things about making plugins, and can just focus your effort on the processing and the interface - plus it has many useful audio/MIDI-related features built-in... :thumbup:

That looks very useful indeed! Thank you!
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Re: What's the most time-consuming part of your post workflow?

Postby Tim Gillett » Wed Feb 12, 2020 10:06 am

MiguelTanhi wrote:Depending on the project, I can have anywhere from 20-100+ clips that all need to go through noise reduction, EQ, normalization, dereverb etc. and they all have specific parameters that need to be factored in depending on the speaker's voice and recording conditions. Noise reduction, alone, can take 5 minutes per clip if there's not an obvious and adequate gap to pull a noise-sample from.

.

Back to the OP, I couldn't help notice the mention of noise reduction and Dereverb.
Both processes are normally a last resort when faulty recordings cant easily be made again. The result is rarely as good as if they'd not been needed, if ever. It can save a lot of time and effort later to make our recordings clean enough that they don't need drastic measures to "rescue" them in post. Also, "clean enough" doesn't mean not needing any further tweaking, but certainly not needing major restorative work.
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Re: What's the most time-consuming part of your post workflow?

Postby Mixedup » Wed Feb 12, 2020 10:36 pm

Martin Walker wrote:I came up with a scheme using several Reaper bundled plug-ins so I could audition just the audio part that was being removed (very useful in various other scenarios!) , which allowed me to remove the transient completely without any of the main body of the sound.

Hi Martin. And a neat scheme it is too... which I gather will be described in full in the forthcoming SOS March 2020 ;)

Have you tried Tokyo Dawn's Limiter 6 GE (the newer one, not the original Limiter No6 by VladG)? For one thing, it's brilliant for limiting/clipping — so much control across multiple stages! For another, there are multiple oversampling options. And for another, like most of their plug-ins, it has a 'delta' function built in so you can listen to the difference between the processed and unprocessed signal really conveniently. A great plug-in and well worth the money. (All the more so now that TDR are gradually rolling out VST3 versions of everything.)
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Re: What's the most time-consuming part of your post workflow?

Postby Arpangel » Sat Feb 15, 2020 9:31 am

I’m desperate for some sort of transparent limiter on record, our marimba is causing major, big trouble. I’ve tried everything, t’s so difficult to record, and it’s incredibly dynamic.
I’m recording at a reference level of -20dB, and it still clips. I’m wondering if I should be looking at a different mic? I’m using Sennheiser MKH mic's, and they have a very high output, very sensitive too, just thought a less sensitive, lower output mic might be more suitable?

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Re: What's the most time-consuming part of your post workflow?

Postby Agharta » Sat Feb 15, 2020 10:12 am

This might give you some ideas when dealing with loud instruments:
https://youtu.be/_-TApnxnCTY
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Re: What's the most time-consuming part of your post workflow?

Postby Arpangel » Sat Feb 15, 2020 10:42 am

Agharta wrote:This might give you some ideas when dealing with loud instruments:
https://youtu.be/_-TApnxnCTY

:D
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Re: What's the most time-consuming part of your post workflow?

Postby Hugh Robjohns » Sat Feb 15, 2020 11:02 am

Arpangel wrote:I’m recording at a reference level of -20dB, and it still clips.

Then record at a 'reference level' of '-30dB'... it really ain't rocket science! The important issue is not to get clipping in the recording! You can sort out the dynamics afterwards.

I’m wondering if I should be looking at a different mic?

Mastering the art of setting an appropriate gain structure would probably be my advice...

Are you absolutely sure it is the DAW that's clipping? Other potential bottle-necks include the mic itself and the preamp, of course. MKH's have a -10dB pad on them for a reason. Have you tried using it?

However, as you have observed the marimba is inherently a very percussive instrument -- and maximally so when close-miked. So using a capacitor mic like the MKH -- which captures transients very accurately -- may not be making your recording life any easier.

Instead, you might well find switching to high-quality dynamic mics makes recording easier because the high inertia of the big lump of copper in the moving-coil behind the diaphragm tends to naturally 'compress' and soften transient peaks. That's one reason why dynamics are generally preferred for miking up drum sets.

I'd probably reach for a pair of M201s in your situation, but any high quality moving-coil mic would be worth a try. And if you don't have, or can't borrow any, you could hire some for a trivial outlay just for one session to see if it helps .

I’m using Sennheiser MKH mic's, and they have a very high output, very sensitive too, just thought a less sensitive, lower output mic might be more suitable?

Nope... Think about it... that would be absolutely no different to simply switching in the -10dB pad on the mics, or even just turning down the preamp gain a bit... things which you're struggling to apply at the moment... ;)

So I suspect all that would happen if you replaced your mics for low sensitivity, low output models is that you'd immediately crank up the preamp gain until you have the same '-20dB reference level' and the same readings on your meters, and then you'd come back here complaining that it's still clipping!

H
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Re: What's the most time-consuming part of your post workflow?

Postby Arpangel » Sat Feb 15, 2020 11:05 am

Hugh Robjohns wrote:So I suspect all that would happen if you replaced your mics for low sensitivity, low output models is that you'd immediately crank up the preamp gain until you have the same readings on your meters and the same -20dBFS reference level, and then you'd come back here complaining that it's still clipping!

H

I don’t know, simple as that, I’ve dropped the level to -30dB on the marimba, I can't even see the b****y wave forms.
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Re: What's the most time-consuming part of your post workflow?

Postby The Elf » Sat Feb 15, 2020 11:07 am

Arpangel wrote: I’m recording at a reference level of -20dB, and it still clips. I’m wondering if I should be looking at a different mic? I’m using Sennheiser MKH mic's, and they have a very high output, very sensitive too, just thought a less sensitive, lower output mic might be more suitable
Then you're still recording too loud - it really is that simple!

Not sure what you mean by 'reference level' - peaks, or average? I always say to aim for peaks absolutely no higher than -10dBFS. Analogue meters can be deceptive with very transient material.

Maybe a barrel pad on the mic will be necessary - assuming your mic's don't have pad switches?

Hugh got to it first! :beamup:
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Re: What's the most time-consuming part of your post workflow?

Postby The Elf » Sat Feb 15, 2020 11:10 am

Arpangel wrote:
Hugh Robjohns wrote:So I suspect all that would happen if you replaced your mics for low sensitivity, low output models is that you'd immediately crank up the preamp gain until you have the same readings on your meters and the same -20dBFS reference level, and then you'd come back here complaining that it's still clipping!

H

I don’t know, simple as that, I’ve dropped the level to -30dB on the marimba, I can't even see the b****y wave forms.
Most DAWs have a zoom function...
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