Noise Reduction

I’m using Windows 10 - with Audacity 2.3.0

I’ve never had this problem before - but now seems to be an issue that I need to deal with. Having recorded, and downloaded to both mp3 and WAV, of many chapters of a book, I’ve been informed that the noise floor is too loud in the final submission. This was never a problem with the previous version of Audacity. The issue is, how do I remove this additional noise once the files have been converted? The “noise sample” is no longer available, since all editing has been completed, with most all “quiet” sections having been totally silenced. Do I have to re-record all the chapters? UGH! Thanks for any assistance you can provide.


Are you following recommendations or or a recipe for production? You said some messy things there.

This is from the ACX web page of recommendations.

Screen Shot 2019-03-19 at 13.18.54.png
Note it does not say “dead silence before and after”. They specifically want Room Tone or background noise in those places.

That may have caused other problems as well. If the Room Tone segments are missing from your submission (the noise would, oddly enough, have been too low), then ACX would have tried to derive Room Tone for noise measurements from your performance. That’s likely to result in silly high noise readings and would have failed ACX Technical Standards.

It is highly recommended that you Export raw readings as WAV files and save them someplace safe against the time that an accident or other event damages the work. In this case you would be opening up those raw readings and processing them properly.

Yes, saving the Edit Master WAV is also highly recommended, but you don’t need the MP3. You can’t edit an MP3 without causing sound damage, but you can make a WAV into anything else at any time.

But wait, there’s more.

ACX wants all the chapters and segments to match, so there’s no going back half-way through the book and patching up all the older segments, or there is, but it’s not for the average user. Record fresh room tone and carefully, surgically attach it before and after each chapter and at all the places you silenced during production. That’s a master class and will only work if the room tone passed ACX quality control in the first place.

I don’t see any way around reading it all again.

Before you do that it might be valuable to submit a sound test on the forum. It’s 20 seconds.


I’ve never had this problem before

Have you recorded multiple books? There was a recent posting from someone else who had his third book submission refused on technical grounds.

The conspiracy theory version of this is someone at ACX has been accepting audiobook submissions with fuzzy technical standards and they started to get complaints. This isn’t a podcast. They’re asking people to part with actual money for a voice performance.

The test clip on the forum is a good idea. We can identify sound problems you may not be able to easily fix.


This was never a problem with the previous version of Audacity.

Maybe if you got a new computer it’s not Audacity. Audacity does not apply effects, filters, corrections or changes while recording—other than under certain conditions, volume.

If you did a Windows or computer change, there could be some serious sound changes in the computer.