GarageBand for Mac: Record to multiple software instrument tracks
You can record to multiple software instrument tracks simultaneously. In order to record to multiple audio tracks, you must have the Record Enable button visible on each track. The Record Enable button prepares multiple software instrument tracks to receive MIDI simultaneously.
During recording, any adjustments to knobs or other controls in the Smart Controls area are recorded as region-based automation. You can Use automation in the Piano Roll Editor to edit the Smart Controls Recording later.
Note: Record enabling a track also lets you monitor the input.
Record to multiple software instrument tracks simultaneously
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.
Use your MIDI keyboard, Musical Typing window, or onscreen music keyboard to play some notes. Record as many cycle passes as you wish.
A new MIDI 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.