Exporting for Audible - Sample Rate and RMS issues

Hi friends,

I’m having a hell of a time with my uploads to the ACX website after recording in Audacity.
My main issue is the Sample Rate. I’ve been recording at 44100, but when I upload, the site says that it’s in 48, and needs to be re-encode it at 41.
I’ve tried the “resample” option as well, but it changes my voice to a slow and low bastardization of the recording.

I’ve also got some issues with RMS, but am slowly figuring those out… kind of.
Anybody have any advice before I pull out all my hair and give up all togeher?


The Project Rate under Audio Settings determines the sample rate when you export. …Rumor is, they’ll be making some changes so you can select it when you export.

There used to be a procedure in the Wiki, but they killed the Wiki. :frowning: And somewhere there is a macro to do it automatically and maybe somebody can give you a link.

Regular-linear volume adjustments make the same dB change to everything, peak, RMS, and noise floor.

From memory, these are the 2 important steps.

1 - Run Loudness Normalization, set to RMS (not perceived loudness) at -20dB. This will usually push your peaks over the limit, and sometimes into potential clipping.

2 - Run the Limiter effect, set to -3.5dB, no input gain or make-up gain. I think Hold should be set to minimum. That will get your peaks into spec with almost no effect on the RMS levels.

Then you may need a little noise reduction but there are no standard settings for that.

I figured it out!
All the videos have the “project rate” in the bottom left corner, as it was always there in older versions of Audacity. Now that I’ve upgraded versions, I’ve lost access to what was once a very simple action. Here’s how to get to it now.

Click the “Audacity” tab at the top.
Open “Preferences”
In the “Audio Settings” tab, look down at the “Quality” section.
There, you’ll see both “Project Rate” (which for Audible should be 44100), as well as "Default Sample Rate. I’ve changed both of those from the defaulted 48000 to our coveted 44100, and am hoping that they stay that way.
Click “OK”, and be on your merry way!

I’m collecting the pieces of the old system.

This is a support document featuring the two most important tools… ACX-Check and Audiobook Mastering Macro.

I posted additional forum notes to someone reading for books.

ACX Check analyzes the work you point it to and gives you a summary post.

Mastering is a little rough to install because it’s a plain text file and computers insist on assuming it’s a written document instead of a program.

Whatever you point Mastering at is going to pass Peak and RMS (loudness). Guaranteed. If you recorded in a quiet, echo-free room, you may be done. Many home microphones will need a little noise reduction and we recommend “Noise Reduction of the Beast” 6, 6, 6. Select some clean background noise (no breathing or gasping) and use that as the Profile. Then apply Noise Reduction to the whole chapter with those settings. Good Noise is quieter than -65dB but louder than -95dB.

I swear I saved one of these messages where I wrote all this stuff down.



Here’s one message threadI saved, but I think there’s a better one.

Scroll through it.


I keep telling myself I’m going to write a global Audiobook Class instead of writing all this stuff down every time. I get into the first class and get depressed.

The forum search term is: “I need to be able to buy your book on Amazon right now.”


I remember this. This is a long, unfortunate forum post that has not yet resolved. Even though the thread is rich in content and notes, its also rich in pitfalls and gotchas. Best left alone.

I do have a goal to see how simple I can read successfully. I think I can do most of it on my phone. Everybody is horrified at the very idea, but the people most horrified are the makers of the home microphones.

Anyway, as we go.


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