How to change the tempo or pitch of Real Audio track with an Imported Audio File
Written for GarageBand 10 or later on a mac
Tracks with imported audio Files do not follow the tempo and pitch, when we change the tempo or pitch of a project, only real audio tracks we record with GarageBand.
When we need to adjust the tempo of an audio file, it helps to create a custom loop from the audio file like this: Create custom Apple Loops in GarageBand on Mac – Apple Support (UK)
- In the Track with the audio file trim the region of the audio file, so it is aligned with the bars of the measures. The length needs to be a full number of measures.
- Select the region, then use the command "File > Add Region to Loop Library" and save the region as a loop, not as a One-Shot loop. Only a loop can follow the tempo and pitch of the project.
Then you can add the song as a loop to a new project and change the tempo by changing the tempo of the project or modifying the tempo using the tempo track.
This has been easier in the old iLife versions of GarageBand. With GarageBand '11 (version 9.x.x) or earlier, we could turn audio tracks with audio files into real audio track simply by selecting them and pressing the keyboard shortcut control-option-g . The color of the regions would turn purple and the track would behave like a real audio track with recorded regions and follow the project tempo.