GarageBand for Mac: Record to multiple audio tracks
You can record to more than one audio track at a time, which allows you to record several instruments at once—placing each instrument on a separate track, for example. The Record Enable button prepares multiple audio tracks to receive audio simultaneously.
Note: Record enabling a track also lets you monitor the input.
Record to multiple audio tracks simultaneously
Set the instrument or microphone input source for each track you want to record to.
Choose Track > Configure Track Header. You can also right-click on any track header or press Option-T. In the Track Header Configuration dialog, select Record Enable.
If Record Enable is already selected, you can skip this step.
Click the Record Enable button in the track header of each track you want to record to.
Move the playhead to the point in the ruler where you want to start recording.
Set the metronome and count-in to hear a steady beat while recording.
Click the Record button in the control bar (or press R) to start recording.
Start singing or playing your instrument.
A new audio region appears on each of the record-enabled tracks.
Click the Stop button in the control bar (or press the Space bar) to stop recording.