Fixing an ACX Issue

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TJB
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Fixing an ACX Issue

Post by TJB » Wed Dec 16, 2020 5:28 pm

On a recent novel I completed, ACX bounced two chapters with the following notation:

• Issue: The production includes files that contain noise at the start and/or tail end. The first 0 to 2 seconds, and the last 1 to 5 seconds of each file must revised to ensure none of them contain any noise, loud breaths and/or mouse clicks at the start before narration begins and at the end after the last spoken word.

In reviewing the sound track for the particular chapter, there are no VISIBLE indicators as to noise, no bumps, no squiggels, etc.

I've attempted today to fix it. Short of re-recording, what I've done today is deleted all the dead space at front and end and , using cut and paste, replaced it with (hopefully) silence. I just sent it back to ACX.

Will that work or is there a better way???

Trebor
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Re: Fixing an ACX Issue

Post by Trebor » Wed Dec 16, 2020 5:41 pm

TJB wrote:
Wed Dec 16, 2020 5:28 pm
..., there are no VISIBLE indicators as to noise, no bumps, no squiggels, etc.
Some audible sounds are not visible on the waveform unless you zoom-in.

It's possible to have bassy thuds in the recording, but not hear them because ones speakers/headphones are not capable of reproducing them, (They would still show up on spectrogram view).

kozikowski
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Re: Fixing an ACX Issue

Post by kozikowski » Wed Dec 16, 2020 5:54 pm

Will that work or is there a better way???
Production Silence isn't dead silent. They have a phrase "room tone," the sound the room makes when the performer isn't making any sound. That's what is supposed to be in there.

If all the other chapters passed, you can borrow the room tone from one of them and paste it in place of the bad segments.

You can step your way down the rings of Hell, here. You can't edit the MP3 you submitted to ACX. You should edit the WAV file master of the book chapter. It's not obvious you need to make WAV files of all your work, but you should.

Remember when you made the MP3s, they had to be constant-bitrate, 192 quality? If you edit an MP3 chapter and resubmit, it won't be 192 any more. MP3 is convenient for listening to music at the beach or submitting to ACX, but not for audio production or editing.

We'll see what they say.

Koz

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Re: Fixing an ACX Issue

Post by kozikowski » Wed Dec 16, 2020 6:17 pm

There are other ways to measure this.

Drag-select some of the offending work (even if you can't see any blue waves). Analyze > Contrast > Measure Selection. That measurement should be -60dB or quieter (ACX). We use -65dB (even quieter) as a recommendation rather than what happened to you, where you're so close that some chapters didn't make it.

You can drag-select your offending area and just run Analyze > ACX-Check again. Ignore the first two values.

You can noise reduce use what you have, but that can be a little more dangerous. Drag some of the bad sound > Effect > Noise Reduction > Profile. Then carefully drag-select the part you want to reduce > Effect > Noise Reduction: 6, 6, 6 > OK.

Measure it again to make sure. Make sure you still pass the two seconds at the beginning and five seconds at the end of Room Tone.

Koz

TJB
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Re: Fixing an ACX Issue

Post by TJB » Wed Dec 16, 2020 9:59 pm

Koz, the original chapter (v2) in question overall has a noise floor of -79.9 so they must be referring to the one second clip at the beginning and the 4.5 piece at the end.

So I ran an ACX check on just the 4.5 section at the end of v2 and it showed a noise floor of -68.6 ... Peak was ok but now said the RMS was less than ACX specs (which I assume is correct since there's no audio on that short clip). I attempted to do the same analysis of the 1 sec clip at the beginning, but that was insufficient for ACX check to work

So, today I did v3 by adding silence to front and back and deleting the old. Now v3 shows an overall noisefloor of -69.1. Then I measured the tail end (the 4.5 sec clip) and it came in at -67.4 ... basically the same as in v2

Soooo ... like you say, let's wait and see, I guess. If you want to take a listen, lemme know and I'll send you the MP3 file. Maybe like you said, there's some invisible sound on that track

Thanx for your help, Tom

kozikowski
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Re: Fixing an ACX Issue

Post by kozikowski » Thu Dec 17, 2020 1:18 am

You do have to be careful what the tools are telling you.

If you've been doing this for a while, you may have the old ACX Check. It had restrictions for show length and is no longer recommended. The new ACX Check is here.

https://wiki.audacityteam.org/wiki/Nyqu ... #ACX_Check

As you noticed, if you turn ACX Check loose on Room Tone, the first two values, Peak and RMS, will be meaningless and only the Noise value is good. If you measure a whole chapter, ACX Check will go through and find the quietest half-second. So you can't make assumptions about the noise of specific areas that way.

If your show does have well-behaved background noise, the tool can measure it anywhere and the reading will be valid. If you start fancy editing, cutting, and messing with compression or other dynamic volume managers, all bets are off. Once you start that, it's possible to get too quiet.

The goal is to sound natural. "Natural" is not speaking over the Blackness of Space.

You did say a couple of odd things about your chapter standards values. Are you using the published ACX Mastering Suite?

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

This is the short version.

Image

You don't have to. This isn't the only way to meet ACX, but it does work pretty well and several posters are using it professionally.

Koz

TJB
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Re: Fixing an ACX Issue

Post by TJB » Thu Dec 17, 2020 5:49 pm

Koz, I do use the mastering scenario you outlined above.

I've completed four books for ACX with none of them being bounced for any reason ... but book 5 has this one chapter that I can't get through. If they reject the fix I sent yesterday, my only recourse is to re-record it.

TJB
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Re: Fixing an ACX Issue

Post by TJB » Thu Dec 17, 2020 5:57 pm

Koz, one more question. When I do the mastering, and I use the Noise Reduction effect, what I've sometimes done is repeat the process thereby often getting the noise to around -80. For example, the original read might be -60 ... I then use the Noise Reduction and it bumps it up to, let's say, -72. Then I'll apply the Reduction again, and now it's at an even higher number, for instance -80

Is this a good idea ?????

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Re: Fixing an ACX Issue

Post by kozikowski » Thu Dec 17, 2020 6:32 pm

Is this a good idea ?????
No. Excessive noise reduction can harm voice quality. The process isn't "free." Your voice starts getting "tight" and wine-glassy.

The ACX standard is quieter than -60dB. We recommend quieter than -65dB and anything in the -70s is good to go.

Are you using a noise reduction of 12? That can cause voice quality issues. Certainly no reduction values higher than that. If you need extraordinary noise reduction you should to go back and fix your microphone or recording system—or studio.

If you're careful about live recording you should be able to hit mastered noise values in the -63dB to -65dB range. Add Noise Reduction of the Beast, 6, 6, 6 and that gives you -70dB. Done. Go make coffee.

Maybe as high as 9, 6, 6.

You can do what you want, but certainly that second application is causing voice quality damage. Remembering that the goal is plain, natural, story-telling voice, not robotic or mechanical voice.

ACX has a failure called "Overprocessing."

Koz

TJB
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Re: Fixing an ACX Issue

Post by TJB » Thu Dec 17, 2020 7:00 pm

Great answer, Koz ... noted and will comply

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