Apple Logic Pro 9 - Manual (Page 222)

Understanding Tracks and Channel Strips
Tracks are listed from top to bottom in the Arrange track list and extend horizontally
across the Arrange area in lanes.
Each track is assigned to a particular channel strip in the Mixer. In other words, the output
of a track is sent to a channel strip. If a track is not sent to a channel strip, regions on it
will not be heard.
Note: The exception to this rule is folder tracks. For more information, see Working with
Folders .
Once assigned to a particular channel strip type in the Mixer, the behavior of the track is
limited as follows:
Track used for Assigned to Mixer Track type
Playback, recording, and automation of audio
regions. Audio channel strips Audio
Playback, recording, and automation of MIDI data
sent to software instruments. Instrument channel
strips Instrument
Playback, recording, and automation of MIDI data
sent to external MIDI devices. MIDI channel strips MIDI
222 Chapter 9 Working with Tracks