After recording, when I did the ACX Check, this is what it said:

Peak Level 0.673164 (-3.4 dB)
RMS 0.097284 (-20.2 dB)
Noise Floor 0.000000 (-inf.dB)

RMS (A) 0.55548 (-25.1 dB)
Noise Floor (A) 0.000000 (292.4 dB)

Clip Meets ACX Requirements

Normally, my recordings are in the normal ranges of between 68 and 76 RMS … what does the -inf dB mean … and is this, in fact, acceptable to ACX ???

It means there’s a section with “digital dead-silence”. You’ve either generated/inserted some silence or somehow completely silenced/muted the audio. ACX will reject it for being unnatural and over-processed.

…Decibels are a logarithmic ratio. Total silence (represented digitally) is a sequence of samples with a numerical value of zero. The log of zero is “minus infinity” (infinitesimally small and not actually defined mathematically). Sort-of the opposite of dividing by zero…

You might get that if you recorded your chapter right after a Zoom call or, in fact, have Zoom “resting” in the background as you read. Skype, Zoom, Meetings, etc., apply corrections, filters, processing, and effects to your voice and you can’t stop it.

You can get that from Windows, too. Google “Windows Sound Enhancements.”

ACX calls that “overprocessing,” particularly if the effect comes and goes and “pumps.”

ACX is looking for natural-sounding speech. My stupid joke is listening to someone telling you a fascinating story over cups of tea, not a ratty Zoom call.

Is this your first book? ACX will no longer do a theatrical evaluation ahead of time, but you can post a short piece here and we can take a listen.


That’s the old ACX-Check. There’s a new one.