The first three values and the sentence 2/3 down are the only readings you need for ACX. Those are the hardware values and are the tests performed by the ACX Robot—the first test in the series for acceptance.
The other values are “Since We’re Here.” Once you go through the craziness of actually programming a test tool, the other numbers are relatively easy to derive, so there they are. The “A” values are similar to the plain values, but they follow, more or less, the ear sensitivity. If you go far enough up in pitch, only dogs can hear it and if you go far enough down, only cats can sense it (earthquake, thunder). But it’s all sound.
If you have someone show up at your place of work with a sound meter testing for hazardous or dangerous sounds, that meter will be using the A restriction. All the stuff most humans can hear. That’s the one built into most laws and codes.
ACX uses the plain readings, dogs or not. So those are the values you have to meet.
A word on noise. The standard value is quieter than -60dB. You should not celebrate if you make it to -60.5dB. You have to make it quieter than that because you have to do it, reliably, over the whole book. The fuzzy rule is -63dB to -65dB.
Further, if you have computer fans or other irritating noises, you can technically make it, but you may fail the second ACX test, Human Quality Control. That’s the one where a real human listens to the work and tests for theatrical reading and presentation quality. That’s the acting test. They’ll never pass one of those screechy laptop fans.
Home readers never pass noise. It’s a lot harder than it looks. Background noise has to be 1000 times quieter than your voice. If you can tell your computer is on just by listening, it’s going to be a long day.
We publish Audiobook Mastering Suite. Three tools that guarantee Peak and RMS (loudness) and if you read in a quiet room, Noise should work by itself.
If you have troubles, post back and include (if you wish) a test sample.
Go down those blue links. It’s pretty short.