Apple Logic Pro 9 - Manual (Page 41)

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 avant-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 four-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—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 something 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).
Not only does this allow you to play up to 64 different sounds simultaneously through
your tone generators, it also allows full MIDI control for each channel of each device. This
becomes increasingly important when arranging and orchestrating such a large number
of instrument parts.
If your computer offers several MIDI inputs, you can connect the MIDI outputs of other
MIDI expanders and controllers to it.
Using USB MIDI Keyboards
If using a MIDI keyboard fitted with a USB connector, you don’t require a separate MIDI
interface, as it is already built into the keyboard. Just be sure to install the driver, if needed,
and connect the keyboard to your computer with a USB cable. Some modern USB
keyboards and controllers are automatically recognized by Mac OS X.
Separating a MIDI Keyboard from Its Sound Generator
If your MIDI keyboard has an internal sound source, it is important that you stop the
keyboard from generating sounds directly from its own keyboard.
41 Chapter 2 Setting Up Your System