Apple Logic Express 7 - Manual (Page 21)

Chapter 2 Instruments and Effects 21
3 Double click the newly-created Audio Object icon, so that the (grayed out) channel
strip appears.
4 Now, go to the Object Parameter box, and set the Channel parameter to an Instrument.
The generic Audio Object will now operate as an Audio Instrument, allowing you to
insert any Instrument plug-in into the instrument slot.
The default song—the song that opens if you move the Autoload Song away from the
Logic folder—features a number of ready-configured Instruments, that can be accessed
via the Track Mixer or Audio Mixer.
The output signal of a software instrument plug-in is fed into the input (the instrument
slot) of the Instrument channel strip, where it can be processed via inserted plug-ins
and/or sent to busses.
Logic supports up to 24 discrete Audio Instruments. The number of instrument
instances which can be run simultaneously is dependent on the availability of
computer processing resources.
Following the insertion of an instrument, the Audio Instrument Object can be used just
like a MIDI track in the Arrange window. The Audio Instrument Object can also receive
MIDI notes from standard MIDI instrument objects via Environment cables. This is
useful for creating layered sounds with “real” MIDI instruments and virtual instruments.
Please note that the Options > Preferences > MIDI > Use Unified Virtual and Classic MIDI
Engine setting needs to be switched on for these features to work.
When an Audio Instrument track is selected, it is ready to be played in real-time and
consequently produces some system load. Normally, Logic releases system resources
used by the Audio Engine when the sequencer is stopped. This is not the case,
however, if an Audio Instrument track is selected in the Arrange window, and is
therefore available for real-time playing. Selecting a MIDI track or a standard Audio
track exits this Audio Instrument “stand by” mode, and releases reserved system
resources when the sequencer is stopped.
Note: Muting an Audio Instrument track in the Arrange does not reduce system load.