Logic Pro 9 User Manual - Help Library - Apple

4 Click the disclosure triangle to the left of the GM Device 1 entry in the Inspector to open
the Track Parameter box, if not already open.
There are two parameters of particular note here: Port and Channel. (See Setting External
MIDI Channel Strip Parameters.)
5 Choose All from the Port pop-up menu.
All of your MIDI interface Out ports are listed; for example, Port 1 (Unitor 8), Port 2 (Unitor
8), MIDI1 (mLan Network). If you choose a specific Port—Port 1 (Unitor 8), for example—the
GM Device multi-instrument object is routed to this specific MIDI port. This mirrors the
port listing shown in the left column of the Library tab.
6 Note that the Channel parameter is set to 1. Create a few new External MIDI tracks by
following steps 1 and 2. These new tracks are called GM Device 2, GM Device 3,
GM Device 4, and so on. Click each of these tracks in the track list, and keep an eye on
the Channel parameter in the Track Parameter box of the Inspector. Each of these tracks
is routed to a sub-channel of the GM Device multi-instrument object. The selection of
each track is mirrored by the 16 sub-channel entries shown in the right column of the
Library tab.
When creating more than one new External MIDI track, Logic Pro does not create a new
multi-instrument object for each one. Rather, it assigns each subsequent track to
sub-channels of the GM Device multi-instrument object. You can create up to 16 tracks
that are assigned on a one-to-one basis with each sub-channel of a multi-instrument
object.
If you need more channels for more external MIDI synthesizers and modules, you have
a couple of options. The easiest way is to use the Library tab to reassign newly created
tracks to particular MIDI ports and channels.
Chapter 10 Working with Instruments and Effects
299