RMS Normalize

Limiter > Soft Limit is the magic one.

Anybody with a ruler, an adding machine and strong coffee can figure out RMS.

How do you intentionally distort a voice wave so the peaks never exceed a set value but without changing overall loudness (RMS) significantly—and do it so nobody can hear the change or tell what you did?

There was an early peak processor called “Leveller.” It was OK, but it used brute force techniques that weren’t always satisfactory. It’s still available in the tool kit under Effects > Distortion.


Hello everyone,

After about two hours clicking around in circles…here goes with a very low-level question. How do install RMS Normalize?

I have been up and down this link: https://manual.audacityteam.org/man/installing_effect_generator_and_analyzer_plug_ins_on_windows.html#nyquist_install

However I cannot for the life of me find where I can actually GET this Nyquist Plug-In Installer that is repeatedly mentioned. Does anybody have a link?

I tried to do it manually per the instructions, but when I go to Library/Application Support I don’t see Audacity listed…is there somewhere else it could be hiding? I tried searching and clicking through everything…

I am on latest Mac Catalina 10.15.3 and Audacity 2.3.2.

Many thanks in advance,

Since 2.3.1 it’s part of Audacity in the Tools menu - go to Tools > Nyquist Plug-In Installer


This may seem like a silly question, but I feel like I’m using this all wrong. I use RMS normalize to get to -20 and ACX Check tells me I’m above the -3.0 limit. I fix the limit, but now I’m under the RMS -20. I just keep going back and forth. Can anyone please assist? Thank you.

I previously posted the solution to that:

Thank you so much! This worked like a dream. Sorry I didn’t go through to see if it was already answered. I was at my wit’s end, having spent nearly 2 hours on 10 minutes of “finished” audio.

Downloaded it but can’t open .ny files. A bit confusing…

Instructions for installing Nyquist Plug-ins in Audacity 2.3.3 (Windows): https://manual.audacityteam.org/man/installing_effect_generator_and_analyzer_plug_ins_on_windows.html#nyquist_install

Hello experienced Audacity users,

I am having a very difficult time getting my RMS levels to pass the ACX requirements. Is there someone out there who I can hire to help me fix this problem by walking me through it in a 1-on-1 Zoom session? If so, would you please email me at [personal information removed]?

Thank you!

The helpers on this forum are volunteers. Due to the large amount of people asking for help, and the few number of people providing help, we are unable to offer personal telephone, email, zoom, home visits,…

Please start a new topic on the macOS forum board and one of the Mac people will send a reply. It may be worth reading through this post first: https://forum.audacityteam.org/t/how-to-post-a-question-on-the-forum/23175/1

The RMS Normalize effect is usually foolproof unless you do something afterwards to mess-up the volume.

If you Normalize to -20dB what do you get with ACX check?

Are you following the [u]Recommended Audiobook Mastering Process[/u]?

That’s the formal instructions. The actual process, if you have all the tools, boils down to this.

If you recorded well in a quiet, echo-free room, you may be done.

If you think you are done, ACX has a way to post a short test. It’s not a good idea to crank through a whole book and only then find out you made an odd but serious mistake on all the chapters.



Note that process is different with the recent Audacity upgrade.


Koz, I set all the settings as you described above and everything worked! It passed ACX Check! I wish I knew better what those settings did to fix my recording, but it worked and I’m thrilled. Thank you!


Sorry to bring up the issue again: I am trying to RMS normalize a group of music pieces (formats: WAV or MP3 or m4a), but fail. When I click “normalize” I get the control of peak amplitude only, not RMS, nor "perceived loudness.
I have already downloaded the rms-normalize.ny program suggested by Steve, and stored it in the plug-ins folder of audacity, but I cannot see any change in the screens and options I get from Audacity.

Help, anybody?

If you upgrade Audacity to the current version (Audacity 2.4.2 https://www.audacityteam.org/download/), the “Loudness Normalization” effect is built-in.

Does this work on Audacity 2.4.2? Because I can’t seem to get it to work. All it’s doing is measuring the RMS. There are no options for altering anything.

The current version of Audacity is 3.0.2 (available via the Audacity website: Audacity ® | Downloads
It has a built-in effect that can do either “Loudness Normalization” or “RMS Normalize”. See here for details: Loudness Normalization - Audacity Manual

Is there now a version for version 3.0.3? Now that it’s 64-bit?
Apparently, 32-bit effects won’t work with the 64-bit version.


Yes, it has a built-in effect that can do either “Loudness Normalization” or “RMS Normalize”. See here for details: Loudness Normalization - Audacity Manual