Mastering and noise reduction


I am using Audacity for the first time (in Mac OS X) and am now done recording the audiobook version of my first book. I have watched many, many videos to familiarize myself with Audacity, its plug ins, ACX requirements, etc. Currently the book is in one large 6 hour and 10 minute file, and I understand it needs to be broken into sections/chapters (and I understand how to do that).

My questions:

  1. I should split the large file into chapters PRIOR to mastering (filter curve, loudness norm, limiter, acx check), correct? Rather than running that on the whole file? This is what I’ve done so far in my test clips and have mostly gotten passes as I’ve tinkered around with it.

  2. I recorded in a very quiet closet with very minimal background sound, and have removed clicks and mouth sounds. I’ve tested out some clips with noise reduction, and while it does make my voice sound clearer (or maybe crisper is a better word?), it then drops my noise floor to obscenely low levels. So…does that mean I shouldn’t bother with noise reduction?

Thanks in advance! I hope I’m not in over my head here, ha! :laughing:

We don’t recommend any videos. The ones we’ve seen are either perfectly correct—for the wrong Audacity—or have errors.

That’s not to say you can’t pick up good hints and tricks. I particularly like the video of the guy recording in his bathroom, and it sounds like it, and he magically converts the voice sound into a studio by throwing a blanket over his head. There are actually hardware home-brew and commercial versions of that blanket.

I don’t know if this appears anywhere, but once you start a project, Do Not Update Anything. The forum is full of people who automatically updated their software at each opportunity and very nasty things happened.

Audacity isn’t a massive corporation with offices of people doing quality control and version testing. We do as well as we can, but problems slip through. Audacity is available on all three computer platforms and multi-languages, so testing is monstrously difficult. There was one recent stability problem that only appeared in one Asian language.

Which version of Audacity do you have? Don’t do any more work until we have a little more info.

Audacity Projects can have stability problems and putting one audiobook in one monster Project is dangerous. This goes hand-in-hand with the Audacity version.

It is recommended that you work chapter at a time rather than continuously updating a single Project. You have to submit to ACX in discrete chapters anyway.

We publish Audiobook Mastering which will turn almost anything into a performance meeting ACX RMS (loudness) and Peak specifications. If you recorded well in a quiet room with no echoes, noise should fall in and that may be all you need.

That’s the long version of these three tools.

We also publish ACX-Check which will tell you if your performance meets all three requirements.

It reports in a nice, brief panel.

You are almost certainly using Noise Reduction wrong. It doesn’t reduce noise to dead zero and it’s not supposed to affect the sound quality. Reduction Recommendations depend on the results from ACX-Check. All these tools hold hands with each other.

I’m not sure where to go with your single, massive Project. Do you let your Mac do Time Machine backups, or do you do any kind of backups manually?

Let’s start with Audacity version. Audacity (upper left) > About.


Hello, thank you so much for your reply! I didn’t get an email when you replied, so I didn’t know until I came to check here - I apologize for the delay.

The videos have been helpful, but only when piecing info from multiple videos together, and even then, yes I have noticed their version is often different than mine.

I am using Audacity 3.0.5

I have seen an option to update every time I open the program, and have thankfully somewhat instinctively decided not to update!

I have split the sections and chapters up. Prior to that I exported the entire file on its own, so it is backed up in case something happens. Moving forward I will edit each section/chapter on its own, as you said to do.

I am familiar enough now with how to use the Audiobook Mastering tools as per the link and screen shot you sent, as well as how to use ACX Check.

I would imagine I was using Noise Reduction incorrectly, then. Because it very much changed the sound and also dropped the noise floor.

Please let me know what other info to share. I’ve been quoted $400+ for someone to edit this audiobook for me and I don’t have that kind of money at this time so I am feeling determined to figure it out on my own, sooner than later! :slight_smile:

Once you get the basics down, I think the most difficult part of ACX production is word damage editing. If you’re cursed with mouth noises (raising hand) fixing that may cause you to rethink your career path.

The rest of it is ‘Put the microphone here,’ ‘Push that button,’ ‘Push this button.’

This posting is as close as I ever came to putting all the tricks in one place. You already know some of this, but further down, it talks about WAV file management and backups.

You’re not trying to read a cookbook, are you?

Can I buy your book right now on Amazon? That’s required.

There’s another New User mistake. People show up with a bushel basket of effects, patches, filters, and corrections wondering about settings and application order. There is a sister posting to this one where we went from overprocessed distortion to clear audiobook voice quality with a few simple tricks and mastering. You can leave the list home.

I think I mentioned in one of those posts that ACX no longer provides Human Quality Control until it’s too late. We can get you going here on the forum, however. Burn and post a voice test using this formula.

That monolog has most of the words that can cause problems. P-Popping, Sibilant SSing, etc.