Apple Logic Express 7 - Manual (Page 213)

Chapter 6 Logic’s Mixing Facilities 213
Audio Instrument Object
The Instrument Object allows you to use virtual Software Instruments within Logic.
Currently, the following are supported: Logic’s own suite of software instruments and
AU compatible instruments. Logic supports up to 64 discrete Audio Instrument
channels, dependent on available CPU resources and system RAM. The advantage of
the integration of sampling and synthesis within Logic is that all tools necessary for
audio recording, sample playback and synthesis plus effects and mixing can occur
within your computer.
The Input Slot of the instrument Object serves as an insert slot for the software
instrument.
After inserting 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
via Environment cables from other MIDI instrument Objects. This is useful for creating
sound layers of hardware MIDI instruments and virtual instruments.
Please note that the Preferences > MIDI > General > Use Unified Virtual and Classic MIDI
Engine setting must be switched on to make use of these features.
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 true, however, if
an Audio Instrument track is selected in the Arrange and is therefore available for real-
time playing. Selecting a MIDI track or a normal audio track exits this “stand by” mode
and releases reserved system resources the next time the sequencer is stopped.
Note: Muting an Audio Instrument track in the Arrange does not reduce system load.