ReplayGain

It is helpful to know whether your volume is correct before exporting your recording to an MP3 file. There is a Nyquist plug-in for Audacity called ReplayGain which allows you to do this. It also provides a facility for Equal Loudness Normalization (ie for amplifying to the required level).

ReplayGain: installation

First, download the latest version from here. You may need to right-click on the link and select Save Link As. Save the file (called ReplayGain.ny) somewhere, then follow the relevant instructions below:

Installing on MacOS 10.14 Mojave

First, make sure you are running the latest version of Audacity, 2.3.0, obtainable from here. When you install Audacity on Mojave you may get a warning message saying that the program will not work on future versions of MacOS. That can be ignored. Hopefully by the time Apple goes beyond Mojave, Audacity will have been updated as well.

Ignore older instructions telling you where to save the ReplayGain.ny file: it actually needs to be stored within the Audacity.app package itself. You'll probably find that in /Applications, called Audacity, and though it looks like a single file it is in fact a package that can be opened.

• Go to the /Applications folder, and find Audacity
• Right click on it, and select Show Package Contents
• Double-click on the contents folder, and go to the plugs-ins subfolder
• Copy ReplayGain.ny there
• Restart Audacity
• You should find ReplayGain as one of the items under the Effect menu (towards the bottom, under the horizontal divider).

If you can't see the entry, make sure that ReplayGain is enabled via the Effect | Add/Remove Plug-ins menu option.

Installing on earlier versions of Mac OSX

First, make sure you are running the latest version of Audacity, 2.3.0, obtainable from here.

• Browse to ~/Library/Application Support/audacity/Plug-Ins and go open the plugs-ins subfolder
• Copy ReplayGain.ny there
• Restart Audacity
• You should find ReplayGain as one of the items under the Effect menu (towards the bottom, under the horizontal divider).

If you can't see the entry, make sure that ReplayGain is enabled via the Effect | Add/Remove Plug-ins menu option.

Installing on Windows 10

First, make sure you are running the latest version of Audacity, 2.3.0, obtainable from here.

• Browse to the folder within This PC. in which Audacity is installed: it's probably under OS (C:), and within that Program Files (x86). You should find an Audacity folder at the top, or near it
• Go to the Plug-Ins subfolder and copy ReplayGain.ny there
• Restart Audacity
• You should find ReplayGain as one of the items under the Effect menu (towards the bottom, under the horizontal divider).

If you can't see the entry, make sure that ReplayGain is enabled via the Effect | Add/Remove Plug-ins menu option.

Installation on Windows 10 is also discussed here.

Installing on earlier versions of Windows

First, make sure you are running the latest version of Audacity, 2.3.0, obtainable from here.

• Browse to the folder in which Audacity is installed (it's probably in somewhere like C:\Program Files\Audacity or C:\Program Files (x86)), and go to the Plug-Ins folder
• Copy ReplayGain.ny there
• Restart Audacity
• You should find ReplayGain as one of the items under the Effect menu (towards the bottom, under the horizontal divider).

If you can't see the entry, make sure that ReplayGain is enabled via the Effect | Add/Remove Plug-ins menu option.

Using the plugin

The author explains use of the plug-in in the Audacity forum here.

There is an explanatory video here.

N.B. Please be aware that this plug-in does not warn you if amplification will cause clipping when you Normalize. Check by View | Show Clipping and then View | Fit in Window. If red vertical lines are showing, this means that the audio has reached a level of volume where your voice may be distorted. If this happens, click Undo to undo the Normalization, and use the Effect | Amplify feature without the Allow Clipping box checked.

Old versions

Note that old versions of the plugin didn't have the ability to do amplification, and some were accessed via the Analyze rather than the Effect menu. That's only likely to be relevant if you are running an outdated version.

Further reading

• More technical details for the ReplayGain plugin can be found here
• General instructions on installing various plugins within Audacity are here. (soem of these instructions are out of date)