# Measure between -23dB and -18dB RMS.

**URL:** <https://forum.audacityteam.org/t/measure-between-23db-and-18db-rms/32770>\
**Category:** Audiobook Production\
**Created:** [January 25, 2014, 7:10pm UTC](https://forum.audacityteam.org/t/measure-between-23db-and-18db-rms/32770 "2014-01-25T19:10:49Z")\
**Posts on this page:** 1\
**Showing post:** 16

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**Author:** ![kozikowski](https://forum.audacityteam.org/letter_avatar_proxy/v4/letter/k/919ad9/32.png) [@kozikowski](https://forum.audacityteam.org/u/kozikowski)\
**Post date:** [February 1, 2016, 9:06pm UTC](https://forum.audacityteam.org/t/measure-between-23db-and-18db-rms/32770/16 "2016-02-01T21:06:16Z")

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**English version of the ACX readings.**

**Peak.** Look at the blue waves on the timeline. The very tips of the waves are _never_ allowed to go all the way up or down. That’s overload (1.0 on the timeline – 0dB on the bouncing sound meters). That can cause audible crunching and distortion. ACX doesn’t even want you to get close, so that’s their -3dB (70%) limit.

**RMS.** Loudness. Root Mean Square is a standard electrical measurement which, when applied to audio, happens to work out to loudness. RMS should be between -18dB and -23 dB.

**Noise.** How loud is the show when you stop talking? This can be a combination of dogs barking next door, air conditioner noise, and the ffffffff noise the microphone is making. All of it lumped into one number. Noise should be quieter than -60dB.

And yes, it’s perfectly possible to have a performance that won’t meet all three at the same time. It’s pretty common for home readers.

It’s also possible to pass ACX-Check and still fail acceptance. If you got there by heavily processing and beating your voice to death, the work will fail **Human Quality Control**. The voice is distorted and the failure is “Overprocessing.”

Koz

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