ACX Check Peak and RMS Issues

Hello, I have a problem. When I use RMS Normalize Plugin, the peak level gets worse and ACX Check Plugin reports an error. If I use “normalize” the peak level is good, but the RMS value is no good anymore. How do I get through the ACX check, where all 3 components (Noise Peak RMS) are ok? :frowning: Thanks :slight_smile:

Yes, that’s normal. For example, if you boost the level by +3dB,the peak, RMS, and noise are all boosted by +3dB.

If you follow the [u]Recommended Audiobook Mastering Procedure[/u] RMS normalization is followed by limiting which “pushes down” the peaks with almost no effect on the RMS level.

Noise can be trickier…

What he said.

Audiobook Mastering guarantees RMS (Loudness) and Peak. You are warned to use all three tools in order, don’t add any in the middle and don’t leave any out. They are a “suite.” A harmonious grouping.

Short version.

Home readers never pass noise. That’s the college course. The background noise when you stop talking needs to be 1000 times quieter than your voice. That’s what -60dB means in English.

I can just get my garage to do that on a Sunday evening with furniture moving pads over the metal door.

There are a lot of other problems, too. You can’t sound like you’re announcing in a kitchen for one example.

ACX will no longer do a theatrical evaluation of your work. But we can.

Post a raw, unprocessed sound sample.


All of the Audiobook Mastering tools are built-in to both Audacity 2.4.2 and Audacity 3.0.2. There are no plugins.

You don’t need any of those tools to post a “clean” sound sample.


There are two serious, non-electronic restrictions for an ACX reading.

– Your book has to be publicly for sale on Amazon. I need to be able to buy it right now.

– The book can’t be on the ACX Forbidden List (scroll down).

There were two forum posters who were on that list. One planned on reading a cookbook and the other a program of Yoga chants.

No word on how they worked out.