Use Audio Units plug-ins with GarageBand on Mac
You can use Audio Units plug-ins and Audio Unit Extensions in your GarageBand projects to add new sounds and effects. Audio Units plug-ins and Audio Unit Extensions are available to purchase from third-party vendors or to download for free on the internet.
There are two types of Audio Units plug-ins and Audio Unit Extensions that you can use in your projects:
Effect plug-ins: These include common audio effects such as reverb, compressors, delays and other unique effects. You can use them on individual audio and software instrument tracks and also on the master track.
Instrument plug-ins: These include pianos, organs, synthesizers and other keyboards, and other instruments. You can use them on software instrument tracks only.
To use Audio Units plug-ins and Audio Unit Extensions, you must first install them on your Mac. Audio Unit Extensions (also known as AUv3) are installed in the Applications folder on your Mac, and Audio Units plug-ins (also known as AUv2) are installed in the Library/Audio/Plug-ins/Components folder. Check the documentation for your Audio Units plug-ins or Audio Unit Extensions for installation instructions and to ensure compatibility with the latest version of GarageBand.
You add Audio Units plug-ins and Audio Unit Extensions to a track (including the master track) in the Plug-ins area. You can turn them on or off, change them, edit their settings and remove them in the same way as with plug-ins included with GarageBand. For more information, see Add and edit effect plug-ins in GarageBand on Mac.
Before using Audio Units plug-ins and Audio Unit Extensions in your GarageBand projects, make sure that the Enable Audio Units tickbox is selected in GarageBand > Settings > Audio/MIDI. See Change Audio/MIDI settings in GarageBand on Mac.
Add an Audio Units effect plug-in
In GarageBand on Mac, in the Plug-ins area of the Smart Controls pane, click an empty plug-in slot, then choose a plug-in from the Audio Units submenu.
Click the centre part of a plug-in slot to open the plug-in window.
Add an Audio Units instrument plug-in to a software instrument track
In GarageBand on Mac, in the Plug-ins area of the Smart Controls pane, click the right side of the plug-in in the Instrument slot, choose either AU Generators or AU Instruments, then choose a plug-in from one of the submenus.
Click the centre part of the Instrument slot to open the plug-in window.
Adding an Audio Units instrument plug-in replaces the original instrument plug-in. You can return to the original instrument plug-in by choosing the patch again in the Library.