Audiobook mastering (In Development and Test)

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steve
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Re: Audiobook mastering (In Development and Test)

Post by steve » Mon Sep 23, 2019 10:15 pm

kozikowski wrote:
Mon Sep 23, 2019 6:39 pm
Since the Limiter is the third step and it follows RMS Normalize which can create intentional "overload", how does it know the original show had clipping?
It doesn't. However, if RMS Normalize creates more than occasional peaks slightly over 0 dB, then you have bigger problems to worry about.
If there is only an occasional peak, slightly over 0 dB, then hard limiting those peaks to 0 dB prior to soft limiting to around -3 dB will not be a problem.
Note that we are talking about hard / soft limiting, not "clipping".
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

kozikowski
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Re: Audiobook mastering (In Development and Test)

Post by kozikowski » Mon Sep 23, 2019 10:44 pm

If there is only an occasional peak, slightly over 0 dB
I think you're being a little optimistic there. If you have a thin, expressive woman's voice recorded properly, you're likely to get a lot more than occasional tips over 0. But yes, I get the one-two punch.

I can't wait to find out which programming step or process is causing that waveform distortion. Is this where you find out that neat, orderly code writing is desirable?

Koz

christop
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Re: Audiobook mastering (In Development and Test)

Post by christop » Thu Sep 26, 2019 10:07 pm

I've verified that the soft limiter step is bit-for-bit identical to Steve's Soft Limiter plug-in. ACX Check says Peak level is -inf dB on the difference signal.

The RMS Normalization step gives slightly different results from using the RMS Normalization plug-in manually. And I mean a verrry slight difference. (In one of my tests, the difference signal between RMS Normalize and my plug-in peaked at -82.2289 dB.) This is because the RMS Normalization plug-in uses a shortcut method to measure the RMS of the signal before amplifying it, which gives slightly inaccurate results that are nonetheless good enough for most purposes.

The only step that causes distortion in my plug-in is the high-pass filtering because of the Butterworth filter. It causes the relative phases of the various frequencies in the speech to become offset from each other, which can leads to higher peaks than in the original.

I don't have a whole lot of experience with Nyquist. Steve, what's your recommendation for doing high-pass filtering with a linear phase filter? I've found some Nyquist code that convolutes a section with a windowed sinc convolution kernel, but I haven't had a chance to play with it yet.

steve
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Re: Audiobook mastering (In Development and Test)

Post by steve » Thu Sep 26, 2019 10:22 pm

christop wrote:
Thu Sep 26, 2019 10:07 pm
Steve, what's your recommendation for doing high-pass filtering with a linear phase filter? I've found some Nyquist code that convolutes a section with a windowed sinc convolution kernel, but I haven't had a chance to play with it yet.
From what I recall, it's tricky, and slow. Audacity's Equalization effect handles this much better, which leads me onto a suggestion; Rather than combining all of the effects in a Nyquist plug-in, why not combine them in a Macro? That would allow you to use the Equalization effect, except there's a catch...

In Audacity 2.3.2 (and I think earlier versions too), there's a bug in the Equalization effect that causes Audacity to crash if you open the Equalization effect from within the Macro Manager. To work around this bug, ensure that the correct Equalization setting is set before adding the effect to the Macro.
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

kozikowski
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Re: Audiobook mastering (In Development and Test)

Post by kozikowski » Thu Sep 26, 2019 11:14 pm

And you'll be competing with this Macro.

viewtopic.php?f=64&t=106820

SelectAll:
Equalization:CurveName="Low rolloff for speech" FilterLength="5007" InterpolateLin="0" InterpolationMethod="B-spline"
RmsNormalize:mode="Independently" target="-20"
Limiter:gain-L="0" gain-R="0" hold="10" makeup="No" thresh="-3.5" type="SoftLimit"


Which appears to work just dandy except for one operational problem. RMS Normalize is not native to any Audacity version including, it seems, the upcoming 2.3.3. So it's close but no cigar. Everybody's looking for a simple, stand-alone mastering solution....which is why we have our hopes pinned on you.

Koz

awuertenberg
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Re: Audiobook mastering (In Development and Test)

Post by awuertenberg » Mon Oct 14, 2019 8:46 pm

I downloaded the macro and it appears in my macro list, but I cannot get it to "do anything". I highlight a section, then Apply Macro, then click on ACX Mastering. But I do not see any changes. What am I doing wrong? I have version 2.3.2
thanks

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Re: Audiobook mastering (In Development and Test)

Post by kozikowski » Tue Oct 15, 2019 3:10 am

It's remotely possible your presentation didn't need mastering. One of the suite's design goals was to create as little sound damage as possible, so with the exception of the equalizer, if the tools aren't needed, they just don't do anything.

I would recommend applying the tools manually and watch what happens to the blue waves. UNDO back out to the original and see if the Macro does the same thing. Use a quiet reading (wave tips at about 50%) so you can see the tools work.

https://wiki.audacityteam.org/wiki/Audiobook_Mastering

This is the quick notes on the process. If you get lost, go for the wiki page.

Screen Shot 2019-10-14 at 20.07.25.png
Screen Shot 2019-10-14 at 20.07.25.png (29.36 KiB) Viewed 1129 times

Have you ever used a Macro before?
Koz

awuertenberg
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Re: Audiobook mastering (In Development and Test)

Post by awuertenberg » Wed Dec 09, 2020 12:59 pm

Sorry that it has taken me so long to respond. Yes, I have played around with macros, with some good experiences. I started with the Bass Cut on the Filter Curve and modified it based upon my microphone, then added the Loudness Normalization, followed by the Soft Limiter and finishing with ACX Check. It seems to be pretty decent.
I've created a 2nd macro using Izotope RX7 DeClick and Mouth DeNoise, chased by Waves NS1.
I am getting a pretty quiet end product.

kozikowski
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Re: Audiobook mastering (In Development and Test)

Post by kozikowski » Wed Dec 09, 2020 3:27 pm

That flat bottom wave several messages up may be the kiss of death even if you can't hear it. ACX is looking for processing errors and flat waves are a billboard that You Did Something That Might Be Evil.
Loudness Normalization
Have you noticed that there is an unintended feature in 2.4.2 Loudness Normalize where RMS and LUFS get crossed? The upcoming Audacity 3.0 doesn't do that, so In my opinion 3.0 may be the first Audacity version that will survive a Mastering Macro clean and with zero damage.

One can only hope.

Koz

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