I know that there are many posts about how to correctly format audio files to meet the ACX specifications. I am new to this, and I am trying to understand what I am doing wrong.

For the requirements, when I figure out how to fix one thing… another problem comes up.

What is the best way to correct the RMS levels?
Which effects do you normally use to edit your work and allows you to have the best results?

I have the ACX check. RMS Normalization. Limiter… Any suggestions are appreciated. Thank you!!!

Follow the [u]Recommended Audiobook Mastering Procedure[/u] (in the correct order) and you’ll nail the RMS & peak requirements every time!

…Noise is usually a trickier issue because most people don’t have a soundproof studio, and sometimes the equipment makes excess noise.

Which Audacity do you have? The current one is 2.4.2 and it has all the production tools built-in, apart from ACX Check which you already have.

Everybody goes straight for the microphone. Not my opinion. If you start with a quiet, echo-free room, you can use almost any functioning microphone or sound recorder.

We published Audiobook Mastering. A suite of tools that get you 2/3 of the way there with no fuss.

This is the short form.

Are you the writer? Is the writer conventionally published? Can I buy the book right now on Amazon in either paper or eBook? ACX changed the requirements a while back.


Thank you. I am not a writer. Just starting out as a narrator.

I am a classroom teacher, and many of the people in my room have told me that I should look into audiobooks.

I should look into audiobooks.

Perhaps instructional podcasts. Videotape your classes. Get a lavalier microphone and make sure you get perfect, clear voice recordings.

You and TED and Royal Institute.

Pick a nice logo and opening animation.

You’ll need to video edit particularly if you have whiteboard drawings or other graphics. You can’t do that with one camera, unless you’re really good with post production gymnastics.

All that may be easier than trying to push an audiobook out.


I’d start with two phones. Video and cover audio on one and the other in your pocket for hero audio. That one will probably need an actual microphone and the on-board Voice Recorder software.


So… I’ve been able to get the ACX check to work for a few times. Now, I have having difficulties with the encoding process. I am going through the steps, which I am attaching, but ACX still finds an error.

Which Audacity are you using? The current Audacity, 2.4.2 doesn’t use the Lame encoder.

File > Export > Export as MP3.

Screen Shot 2020-11-25 at 11.20.05.png
That’s it. That’s the whole export process.


Thank you for your help! I was using an encoder, but as you showed, I just needed to change how I was exporting it.

Thank you so much!!!