Apple Logic Pro 9 - Manual (Page 306)

7 Insert the effects in the Insert slots of the channel strip.
As the track is routed to an instrument channel strip (which is being used for an external
MIDI sound module), it behaves just like a standard software instrument track, which
means that you can record and play back MIDI regions on it—with the following benefits:
• You can take advantage of the sounds and synthesis engine of your MIDI module, with
no overhead on your system processor (apart from the effects used on the channel
strip).
• You can use insert effects, obviously, but can also use Send effects by routing the
instrument channel strip to aux channel strips.
• You can bounce your external MIDI instrument parts—with or without effects—to an
audio file, in real time. This makes the creation of a mix, inclusive of all internal and
external devices and tracks, a one-step process.
Note: You cannot use the Freeze function on such tracks, nor can you perform an offline
bounce.
Playing Software Instruments
Software instrument plug-ins respond to MIDI note messages, whereas effect plug-ins
do not.
The output signal of a software instrument is fed into the input (the Instrument slot) of
the instrument channel strip, where it can be processed via inserted effect plug-ins, or
sent to busses.
Logic Pro supports up to 255 discrete instrument channel strips. The number of software
instruments that you can run simultaneously depends on the computer-processing
resources available.
After an instrument plug-in is inserted, the instrument channel strip can be driven by a
recorded MIDI region, or direct MIDI input—playing your MIDI keyboard, in other words.
Understanding Live Mode
Live mode instruments need to stay in Live mode while the audio engine is running
(when Logic Pro is in playback or record mode), because switching a software instrument
track out of Live mode creates a gap (or noise) in the audio stream. Obviously, this is
unacceptable.
Software instruments that are live (ready for playing) require considerably more processing
power than those that are merely playing back existing regions. If selecting a software
instrument track automatically activates Live mode, switching between multiple instrument
tracks would compound the problem, possibly resulting in system overloads.
306 Chapter 10 Working with Instruments and Effects