Revision needed to audition

Hello, a file I submitted with ACX mastering applied failed (it is not related to an audiobook project) as
“Over-compressed/limited. Please use the compressor/limiter feature sparingly.”
I applied a limiter to the original recording as seen on the screenshot. You will also see my biggest peaks.
I do not know what to make of this instruction. Should I re-record my voice and try to have lower peaks overall, or should I decrease the limiter?

They seem to be complaining about a lack of dynamic-range.
Using a lower RMS-normalization level, (say -21dB rather than -18dB),
before applying the limiter* will increase the dynamic-range.

[ BTW use the low frequency roll-off equalization before using RMS normalization & limiter ].

The Audiobook Mastering Suite will guarantee Peak and RMS to any reading. You should use all the tools in order and not add any or leave any out. They’re designed to work from a good, stable, raw reading and don’t correct human errors such as lip smacks, gasps or other wet mouth noises.

Screen Shot 2020-02-15 at 4.16.02.png
If you read in a quiet, echo-free room, the result will pass Noise, too.

If you failed ACX Quality Control, the bad news is they generally complain about the worst problem. You may have others.

We can do a quick evaluation if you want. Post a voice sample on the forum according to this formula.



You can get that if you didn’t turn the Windows Enhancements off or you’re announcing on a Skype, Conferencing, Chat or Games machine. All those things can affect the recorded voice—usually making it sound processed, compressed, or squashed.

In those cases, the Mastering Suite of tools will force your voice and the damage to pass ACX technical requirements, but fail Human Quality Control later when a real person listens to it.

If you struggle with this too long, the suggestion is stop recording on the computer.


Hello both,
thank you so much for trying to help!
@koz: the audio file DOES pass ACX requirements after mastering. The human listening to it though says it is overcompressed and I never heard of that before. I follow the mastering procedure exactly as stated in your post (I learnt how to do it on this forum), every single time and I record in the same environment every time. Both the audiobooks I produced passed QA at once. So now I really don’t know what to do about this complaint rather than re-record and make sure I have no big peaks in the original recording before applying the mastering process.
@Trebor: I set target RMS to 20,5 already :-/
See my screenshot for specs.

Racing Posts.


The attack* looks very steep in some places, (compression will do that).

Free plugins like Audio assault’s “Transient” can be used to make the attack less steep: less percussive.

[ * attack is the slope of the envelope when the sound begins ]