# Help! Balancing ACX specs **URL:** \ **Category:** Audiobook Production\ **Created:** [May 7, 2020, 8:20pm UTC](https://forum.audacityteam.org/t/help-balancing-acx-specs/56827 "2020-05-07T20:20:41Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![pits](https://forum.audacityteam.org/letter_avatar_proxy/v4/letter/p/b782af/32.png) [@pits](https://forum.audacityteam.org/u/pits)\ **Post date:** [May 7, 2020, 8:20pm UTC](https://forum.audacityteam.org/t/help-balancing-acx-specs/56827/1 "2020-05-07T20:20:41Z")
Hi folks, I’m hoping a more experienced Audacity user can help! I’ve got a bucket of files to remaster to specs but can’t get all 3 requirements to ‘PASS’ the Acx Check plugin. Here’s some typical values I get before being stymied: Peak Level: 3.0 (pass) RMS Level: -27.7 (fail) Noise floor: -86.5 (pass) I normalize, compress, normalize again, tweak RMS…can’t pass all 3 specs. Any solutions out there? ---
**Author:** ![kozikowski](https://forum.audacityteam.org/letter_avatar_proxy/v4/letter/k/919ad9/32.png) [@kozikowski](https://forum.audacityteam.org/u/kozikowski)\ **Post date:** [May 7, 2020, 8:48pm UTC](https://forum.audacityteam.org/t/help-balancing-acx-specs/56827/2 "2020-05-07T20:48:21Z")
> I’ve got a bucket of files to remaster Remaster? Have you got the original readings—before you did anything to them? We publish an Audiobook Mastering Suite of tools. Apply them all, in order, don’t add any steps and don’t leave anything out. ![](https://forum.audacityteam.org/uploads/default/original/3X/1/6/1675c89f4a9618d7b07c47527089492886f6ab70.jpeg) The settings should stick. Once you put the numbers into the tool, they should stick there time after time. I can rack through the whole pile in about 20 seconds. That’s taken from here which is a more detailed explanation and will tell you where to get tools from if you don’t have them all. > **[Missing features](https://support.audacityteam.org/troubleshooting/missing-features#audacity-wiki)** > > This page lists features which got removed from Audacity, as well as their replacements. The suite guarantees ACX Peak and ACX RMS (loudness) and if you recorded in a quiet, echo-free room, you may pass Noise and be done. However. If we’re following someone else processing, this may not go so well. ACX is sensitive to funny sounding voices from having applied too many effects or effects with too strong a setting. There is no making a trash recording and beating it with a stick until it passes. It may pass the _technical_ restrictions but it will never pass Human Quality Control where a real person listens to it. These are descriptions of numbering values and the ACX Specifications. > [@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… > [@AudioBook Mastering version 4](https://forum.audacityteam.org/t/audiobook-mastering-version-4/45908/68): > > dB or Decibel Relationships \<— Quieter ———————— Louder —\> -65dB, -60dB, -23dB, -18dB, -3dB, 0dB That’s all the audiobook dB specifications. — Maximum volume is 0dB. Sound gets quieter with negative numbers. — -3dB is the loudest audiobook peak sound value. — RMS or loudness needs to hit between -18dB (louder) and -23dB (quieter). — Noise value has to be quieter than -60dB. Noise is the troublesome one. Actual submitted performance background noise should be quieter than -65dB in real… Post back if you get stuck anywhere. Koz ---
**Author:** ![pits](https://forum.audacityteam.org/letter_avatar_proxy/v4/letter/p/b782af/32.png) [@pits](https://forum.audacityteam.org/u/pits)\ **Post date:** [May 8, 2020, 2:15am UTC](https://forum.audacityteam.org/t/help-balancing-acx-specs/56827/3 "2020-05-08T02:15:46Z")
Success! Thanks much, Koz. I don’t have the ‘Limit Curve’ plugin on my version of Audacity, but learned that it’s a later version of the ‘Equalization’ effect. The required fields are also in Equalization, so I tweaked them, applied the RMS Norm & Limiter effects and it worked perfectly. Looking forward to remastering my bucket of audiobook files. BTW: Yes, the files WERE previously mastered, but thankfully not so radically that the remedy didn’t work 🙂 ---
**Author:** ![kozikowski](https://forum.audacityteam.org/letter_avatar_proxy/v4/letter/k/919ad9/32.png) [@kozikowski](https://forum.audacityteam.org/u/kozikowski)\ **Post date:** [May 8, 2020, 9:45am UTC](https://forum.audacityteam.org/t/help-balancing-acx-specs/56827/4 "2020-05-08T09:45:05Z")
That equalizer curve is kind of a big deal. You can recreate it manually from here. [https://forum.audacityteam.org/t/how-can-i-save-a-filter-curve-that-i-created-to-survive-my-re-installation-of-my-pc-with-win-10/56803/3](https://forum.audacityteam.org/t/how-can-i-save-a-filter-curve-that-i-created-to-survive-my-re-installation-of-my-pc-with-win-10/56803/3) These are the text points. [LowRolloffForSpeech.txt](https://forum.audacityteam.org/uploads/short-url/neXbWEapIdac4nE2HJvkc4hEPWG.xml) (299 Bytes) And this is the XML file you could import into earlier equalizers [LF\_rolloff\_for\_speech 2.xml](https://forum.audacityteam.org/uploads/short-url/neXbWEapIdac4nE2HJvkc4hEPWG.xml) (299 Bytes) The curve is a balancing act between getting rid of “rumble” sound which many home microphones and sound system have (and can throw off the other tools) and affecting the voice. This filter or one like it shows up on field sound mixers and helps with wind, thunder, earthquake and other low pitch interference. If you’re using an earlier Effect Equalization, the length slider should be about 5000. Koz