Apple Logic Pro 8 - Manual (Page 892)

892 Chapter 39 Working in the Environment
GM Mixer
The GM mixer is a collection of 16 fader modules, configured to emulate a virtual
mixing desk for 16 MIDI channels. Each module has controls for volume, mute, preset,
bank, and four assignable knobs (one of which is typically used for pan). There are
optional controls for standard XG and GS effects.
To create a new GM mixer:
m Choose New > GM Mixer.
The GM mixer is intended for controlling the 16 channels of a MIDI device which
conforms to the GM, XG, or GS standard. This includes the GM set of 128 program
names (with variation banks for XG or GS), MSB/LSB bank select messages, and
standard controller names (#1 for mod wheel, #2 for breath, #7 for volume, #10 for pan,
#11 for expression, and so on).
The Parameter Box of the GM Mixer
Most of the GM mixer’s set up is done in the mixer itself, but there are also a few
parameters in its Parameter box.
Port and Channel
Like the instrument and multi instrument objects, the GM mixer can also have a direct
MIDI output connection. It is set with the Port parameter.
The Channel parameter determines the channel number of the lowest GM mixer
module. You can use this (coupled with resizing the GM mixer) to create sub-mixers for
any continuous string of MIDI channels (1 to 4, for example).