# ACX Check plugin - region

**URL:** <https://forum.audacityteam.org/t/acx-check-plugin-region/52345>\
**Category:** Windows\
**Created:** [March 27, 2019, 3:52pm UTC](https://forum.audacityteam.org/t/acx-check-plugin-region/52345 "2019-03-27T15:52:12Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**Author:** ![kozikowski](https://forum.audacityteam.org/letter_avatar_proxy/v4/letter/k/919ad9/32.png) [@kozikowski](https://forum.audacityteam.org/u/kozikowski)\
**Post date:** [March 27, 2019, 9:25pm UTC](https://forum.audacityteam.org/t/acx-check-plugin-region/52345/3 "2019-03-27T21:25:53Z")

</div>

> nor what it’s looking for.

ACX publishes technical specifications for audiobook sound submission. There’s only three: overload protection (Peak), loudness (RMS) and background noise volume.

> [@Measure between -23dB and -18dB RMS.](https://forum.audacityteam.org/t/measure-between-23db-and-18db-rms/32770/16):
>
> 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 s…

That would seem simple but everybody fails noise because the specification means your background noise (room tone) has to be 1000 times quieter than your voice. Nobody can meet that in the average home or apartment. We’re all living in noise bubbles.

Koz

---

_[View the full topic](https://forum.audacityteam.org/t/acx-check-plugin-region/52345)._