Manual

Chapter 4 Setting Up Your System 93
Using Multi-Channel MIDI Devices
Most modern MIDI tone generators can simultaneously receive MIDI data on multiple
MIDI channels (multi-timbral MIDI devices). Each MIDI channel can be assigned a tone/
sound, such as piano, strings, bass, and so on.
To take full advantage of the capabilities of each connected multi-timbral device, you
need to use separate MIDI Out ports (from the computer MIDI interface to the MIDI In
ports) for each device. To explain further, imagine a scenario where:
 There are four MIDI tone generators that are capable of receiving data on multiple
channels.
 All devices can receive on all 16 MIDI channels
 There is only one MIDI Out from the computer, and all devices are daisy-chained via
MIDI Thru to MIDI In connections
Logic Pro is capable of channelizing MIDI data (routing it to MIDI channels 1 to 16) and
is also capable of sending this channelized data to specific MIDI Out ports.
Unfortunately, in the scenario above, there is only one MIDI Out port available.
As such, all data sent on MIDI channel 1 will be sent to all four of the daisy-chained
MIDI tone generators. Each MIDI tone generator will play the incoming data with the
sound assigned to channel 1, which may be:
 Bagpipes on module 1
 A drumkit on module 2
 A helicopter effect on module 3 and so on
While this would be colorful, it would hardly be musical, unless your tastes lean
towards the avante-garde. The same applies to the other 15 MIDI channels.
MIDI, as you can see from the example, can be separated onto 16 different channels,
but it can’t be separated between devices, unless a multi output MIDI interface is used.
Using the scenario above, but substituting a single output MIDI interface with a 4
output MIDI interface—connected from MIDI Out ports A, B, C, and D—to the
respective MIDI In ports of each device. There are no MIDI Thru connections, which
allows Logic Pro to assign and send:
 A recording/performance on MIDI channel 1 to port A/module 1.
 A separate recording/performance—also on MIDI channel 1—can be sent to port B/
module 2.
 A further recording/performance on MIDI channel 1 to port C/module 3, and so on
with subsequent channels and modules.
In effect, having a multi output MIDI interface is somewhat like having more MIDI
channels. In this scenario, it would be like having 64 independent MIDI channels—with
16 channels per port (A, B, C, and D).