RMS Level Limiter - README for macOS / AU / VST3

Thank you for downloading RMS Level Limiter.

RMS Level Limiter is an audio limiter designed to control level based not only on instantaneous peaks, but also on the average energy of the signal = RMS.

A conventional peak limiter mainly reacts to momentary waveform peaks.
RMS Level Limiter is designed to provide more natural level control by monitoring the RMS level, which represents the average signal energy over a given period of time.

Version 1.0.1 Changes:

- Added support for an Apple-notarized installer
- Added support for mono tracks
- Fixed other minor issues


Important:
The macOS version of RMS Level Limiter supports AU / Audio Unit and VST3.
An AAX version is not included.

Use the AU version with Logic Pro, GarageBand, MainStage, and other AU-compatible DAWs.
Use the VST3 version with VST3-compatible DAWs.


1. Overview

RMS Level Limiter is a limiter that applies RMS-based level control and peak safety control to audio signals in your DAW.

Typical uses:

- Controlling the average level of a master track
- Stabilizing levels on drum buses, synth buses, and loops
- Controlling sudden peaks while maintaining a natural sense of loudness
- Visually monitoring RMS level, peak level, and gain reduction

RMS Level Limiter is not designed simply to crush peaks aggressively.
Its purpose is to control perceived level while monitoring the average energy of the signal.


2. Main Features

■ RMS-Based Limiting

RMS Level Limiter applies gain reduction based on the average energy of the signal over a given period of time rather than only on instantaneous maximum peaks.

This allows it to respond more naturally to perceived loudness than a limiter that reacts primarily to peaks.


■ RMS WINDOW / RMS Detection Time

RMS WINDOW sets the averaging time used to calculate the RMS level.
Shorter settings react more quickly to level changes, while longer settings average out small fluctuations for smoother operation.

FAST (50 ms):
Suitable for kicks, bass, drums, percussion, and other material where you want faster response to transients and rhythmic changes.
It captures short-term level changes more easily, but depending on the settings, RMS GR may move more actively, so adjust it together with Attack / Release.

MID (300 ms):
A general-purpose averaging time similar to the response of a VU meter.
This is a useful default setting for vocals, guitars, and general music material when you want to stabilize level while maintaining a natural sense of loudness.

SLOW (600 ms):
Suitable for pads, sustained sounds, synths, mix buses, and mastering, where you want to average out small fluctuations and smooth the overall level.
It reacts more gradually to long-term signal density rather than to momentary changes.

The default setting is MID (300 ms).
When changing modes, the RMS detection state is not reset abruptly. The transition is smoothed over a short period of time to reduce clicks and sudden changes in RMS GR.


■ Peak Safety Control / Safe Level

RMS-based processing alone may leave some instantaneous peaks untreated.

RMS Level Limiter includes Safe Level as a safety ceiling for peaks.
Safe Level operates separately from the RMS processing and applies protective control to the peak level.

Important:
RMS GR shows gain reduction applied in response to the RMS level.
Safe GR shows gain reduction applied to peaks that exceed Safe Level.

For this reason, the Safe Level reference line is most useful when viewed on the Peak L/R meters.


■ RMS / Peak Meters

RMS Level Limiter is designed so that RMS levels and peak levels can be monitored separately.

RMS L/R:
Displays the average signal energy of the left and right channels.

Peak L/R:
Displays the instantaneous peak levels of the left and right channels.

RMS GR:
Displays the amount of gain reduction applied by the RMS limiter.

Safe GR:
Displays the amount of gain reduction applied by the peak safety control when the signal exceeds Safe Level.


■ Natural Level Control

RMS Level Limiter is designed to control perceived level rather than aggressively crush peaks.

It is useful for drums, bass, synths, sample loops, master outputs, and other material with unstable average levels.


■ Mono / Stereo Track Support

Version 1.0.1 adds support for mono tracks in addition to stereo tracks.

In AU-compatible DAWs such as Logic Pro, RMS Level Limiter can now be inserted on mono audio tracks and mono input channels as well.


■ BYPASS

When BYPASS is enabled, RMS Level Limiter processing is disabled so you can compare the processed signal with the original signal.

To avoid being misled by loudness differences, we recommend comparing the level carefully between BYPASS and processed states.


3. System Requirements

Supported OS:
Intel Mac: Tested on macOS 10.15 Catalina
Apple Silicon Mac: macOS 11 or later

Supported CPU:
Apple Silicon Mac / Intel Mac

Supported Formats:
AU / VST3

Recommended System:
Intel Core i5 or higher, Apple M1 or higher, or an equivalent CPU is recommended.
Because RMS Level Limiter performs high-precision DSP processing internally, CPU usage may be higher on older Macs.


4. Installation

Version 1.0.1 uses an Apple-notarized installer.

Open the included installer and follow the on-screen instructions.

The installer places the AU / VST3 versions of RMS Level Limiter in the standard system plug-in folders shown below.

AU:
/Library/Audio/Plug-Ins/Components

VST3:
/Library/Audio/Plug-Ins/VST3

Normally, you do not need to copy the plug-in files manually.

After installation is complete, launch your DAW.
If your DAW is already running, quit it completely and restart it.

After the DAW has completed its plug-in scan,
select RMS Level Limiter from the Push and Groove category.


5. About the Apple-Notarized Installer

The Version 1.0.1 installer is distributed as an Apple-notarized package.

This means that you normally do not need to use the xattr command in Terminal to remove quarantine attributes as with previous unsigned distribution methods.

In most cases, simply open the installer and follow the on-screen instructions.

Depending on your macOS version and security settings, a confirmation dialog may appear.
If so, review the message and continue with the installation.


6. If the Plug-in Does Not Appear After Installation

If RMS Level Limiter does not appear in your DAW after installation, check the following:

1. Quit your DAW completely and restart it.
2. Rescan AU / Audio Unit or VST3 plug-ins using your DAW's plug-in manager.
3. Confirm that the plug-in has been installed in the following folders.

AU:
/Library/Audio/Plug-Ins/Components

VST3:
/Library/Audio/Plug-Ins/VST3

4. If it is still not recognized, restart your Mac and launch the DAW again.


7. About Mono Tracks

Version 1.0.1 adds support for mono tracks.

In previous versions, RMS Level Limiter could appear in the plug-in manager in DAWs such as Logic Pro while not appearing in the insert list for mono tracks.

Version 1.0.1 improves this behavior and supports both mono and stereo audio tracks.


8. Rescanning AU / VST3 Plug-ins

AU / VST3 plug-ins may be cached by macOS or by your DAW.
If RMS Level Limiter does not appear after installation, quit the DAW completely and restart it.

If it still does not appear, rescan AU / Audio Unit or VST3 plug-ins using your DAW's plug-in manager.

Logic Pro:
Open Plug-in Manager and check whether RMS Level Limiter is recognized.
Rescan it if necessary.

GarageBand:
Quit GarageBand completely and restart it.
If the plug-in still does not appear, refresh the Audio Unit cache in macOS.

MainStage:
Open Plug-in Manager and check the recognition status of the AU plug-in.

Ableton Live:
Open Preferences > Plug-Ins and confirm that Audio Units are enabled.
Rescan if necessary.

REAPER:
Open Preferences > Plug-ins > AU and rescan the AU plug-ins.


9. Basic Usage

RMS Level Limiter is used as an audio effect.
Insert it on an instrument track, audio track, bus, or master track.

Basic Routing:

Audio Track / Instrument Track / Bus / Master
-> RMS Level Limiter
-> Audio Output

Steps:

1. Insert RMS Level Limiter on an audio track, bus, or master.
2. Check the RMS and Peak meters.
3. Adjust the amount of RMS limiting.
4. Set Safe Level so that peaks do not excessively exceed your desired safety ceiling.
5. Watch RMS GR and Safe GR while adjusting the settings so the sound is not over-compressed.
6. Use BYPASS to compare the processed signal with the original signal.


10. Recommended Uses

■ Master RMS Control

Use this when you want to naturally control the average level of the master output.
Adjust the settings so that RMS GR is not constantly applying excessive gain reduction.

Guideline:
Start with settings where RMS GR reacts lightly.


■ Drum Bus Leveling

Use this when you want to slightly reduce average level differences between kicks, snares, hi-hats, and other drum elements.
Using Safe Level together with RMS limiting also makes it easier to control strong transient peaks.


■ Synth / Loop Control

Suitable for synth pads, sequences, sample loops, and other material with large variations in level.


■ Peak Safety Check

When checking for unexpected peaks on the final output, adjust the settings while watching Peak L/R and Safe GR.
If Safe GR is constantly applying large amounts of gain reduction, consider reducing the input level or the amount of RMS processing.


11. Notes

■ RMS Levels Are Normally Lower Than Peak Levels

Because RMS represents average signal energy, it will normally display a lower level than the Peak meter.
This is normal behavior.

Peak represents the instantaneous maximum value, while RMS represents the average level over a given period of time.


■ Difference Between RMS Limiting and Peak Limiting

An RMS limiter can respond more naturally to perceived loudness, but peak safety control is still necessary if you need to control instantaneous peaks.

RMS Level Limiter displays RMS GR and Safe GR separately, allowing you to distinguish between processing applied to average level and processing applied to peaks.


■ Avoid Excessive Gain Reduction

If RMS GR or Safe GR is constantly applying large amounts of gain reduction, the sound may become overly compressed, lose attack, or begin to sound distorted.

For natural level control, start with light gain reduction.


■ About True Peak

Safe Level is designed as a peak safety control, but depending on the specifications of the distributed version, it may not provide a complete guarantee against True Peak / inter-sample peaks.

For mastering intended for streaming or other applications that require strict loudness compliance, we recommend confirming the final output with a dedicated metering tool as well.


12. Troubleshooting

■ No Sound

- Confirm that RMS Level Limiter is inserted on an audio track, bus, or master.
- Insert it as an audio effect, not in a MIDI-only plug-in slot.
- Confirm that the plug-in is not bypassed in your DAW.


■ Plug-in Does Not Appear in the DAW

- Confirm that installation completed successfully using the Version 1.0.1 installer.
- Quit your DAW completely and restart it.
- Rescan AU / Audio Unit or VST3 plug-ins in your DAW.
- Confirm that the AU version is installed in /Library/Audio/Plug-Ins/Components and the VST3 version is installed in /Library/Audio/Plug-Ins/VST3.
- Restart your Mac if necessary.


■ Does Not Appear in Logic Pro

- Open Logic Pro's Plug-in Manager and confirm that RMS Level Limiter is recognized.
- Rescan it if necessary.
- Quit Logic Pro completely and restart it.
- If it does not appear on mono tracks, confirm that you are using RMS Level Limiter Version 1.0.1 or later.
- If it is still not recognized, restart macOS and check again.


■ Does Not Appear in Ableton Live

When using RMS Level Limiter in Ableton Live, Audio Units must be enabled if you are using the AU version.

Open Preferences > Plug-Ins, confirm that Audio Units are enabled, and rescan if necessary.


■ VST3 Version Does Not Appear

RMS Level Limiter supports both AU / Audio Unit and VST3.

If it does not appear in a VST3-compatible DAW, confirm that it is installed in the following folder:

/Library/Audio/Plug-Ins/VST3

Then rescan VST3 plug-ins in your DAW.


■ RMS GR Moves but Safe GR Does Not

Safe GR reacts when peaks exceed Safe Level.
If the peak level does not reach Safe Level, Safe GR may not move.

This is normal behavior.


■ Safe GR Moves but RMS GR Barely Moves

If only instantaneous peaks are high while the average level does not enter the RMS limiter's operating range, only Safe GR may react.

This indicates that the peak safety control is operating.


13. License Terms

Copyright:
Copyright of this software belongs to Push and Groove.

Disclaimer:
The developer assumes no responsibility for any direct or indirect damages resulting from the use of this software,
including hardware failure, data loss, or corruption of production data.
Use this software at your own risk.

Prohibited Actions:
Decompiling, modifying, redistributing, or selling this software without permission is prohibited.


14. Third-Party Licenses

This software was developed using the following frameworks and SDKs.

iPlug2 Framework:
Licensed under the zlib-like license.

Audio Unit / AU:
Audio Unit is a technology by Apple Inc.

For the full text of each license, please refer to the official website or source code repository of the respective developer.


15. Trademarks and Disclaimer

RMS Level Limiter is an independently developed product by Push and Groove.
Apple, Logic Pro, GarageBand, MainStage, Audio Unit, AU, macOS, and other product names are trademarks or registered trademarks of their respective owners.

This software is not an official product, official emulation, or officially affiliated product of any of those companies.


16. Credits

RMS Level Limiter
Developed by Push and Groove

(C) 2026 Push and Groove. All rights reserved.
