Apple Logic Pro 8 - Manual (Page 247)

Chapter 10 Working With Instruments and Effects 247
As the track is routed to an instrument channel (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 Macintosh CPU (apart from the effects used on the
channel).
 You can use insert effects, obviously, but can also use Send effects by routing the
Instrument channel to aux channels.
 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 can not 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 channels. The number of software
instruments that you can run simultaneously is dependent on the computer processing
resources available.
Following the insertion of an instrument plug-in, the instrument channel can be driven
by a recorded MIDI region, or direct MIDI input—playing your MIDI keyboard, in other
words!
Switching Instruments to Software Instrument Live Mode
When you select a (software) instrument track, it does not immediately switch into live
or performance mode. You must send a MIDI event before live mode is activated, but
this takes around 100 milliseconds to engage, which is more than enough to destroy
the timing of your first played note.
If you require perfect timing for the first played note, you need to send silent MIDI
events in advance; press the sustain pedal, make a small move of the pitch bender or
modulation wheel as examples. This will switch on live mode.