Apple MB792Z/A User Manual - Page 41

Using USB MIDI Keyboards, Separating a MIDI Keyboard from Its Sound Generator, per port A, B, C

Page 41 highlights

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. For example, if you buy a new keyboard that is to be used without a sequencer, and connect it to an amplifier, you would expect the device to make a sound when you press its keys-in other words, the keyboard is directly connected to the sound generator. When using the MIDI keyboard with Logic Express, however, this is not desirable. In this situation, the keyboard is used as a computer input device, and Logic Express passes the incoming performance information back to the keyboard's sound generator (or to an internal software instrument or another connected sound module, if you like). If the direct connection between the keyboard and its tone generator isn't cut, a doubling of each note results-one played directly from the keyboard to the internal tone generator, and another sent through Logic Express back to the tone generator. Not only does this cause a phased sound, but it also halves the polyphony of the keyboard's tone generator. In situations where you want to control or record another sound module or software instrument with your keyboard, you would hear both the keyboard sound (due to the direct keyboard to tone generator connection) and the sound of the software or MIDI instrument. This is why the keyboard must be separated from its own internal sound generator. Chapter 2 Setting Up Your System 41

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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.
For example, if you buy a new keyboard that is to be used without a sequencer, and
connect it to an amplifier, you would expect the device to make a sound when you press
its keys—in other words, the keyboard is directly connected to the sound generator.
When using the MIDI keyboard with Logic Express, however, this is not desirable. In this
situation, the keyboard is used as a computer input device, and Logic Express passes the
incoming performance information back to the keyboard’s sound generator (or to an
internal software instrument or another connected sound module, if you like).
If the direct connection between the keyboard and its tone generator isn’t cut, a doubling
of each note results—one played directly from the keyboard to the internal tone generator,
and another sent through Logic Express back to the tone generator.
Not only does this cause a phased sound, but it also halves the polyphony of the
keyboard’s tone generator. In situations where you want to control or record another
sound module or software instrument with your keyboard, you would hear both the
keyboard sound (due to the direct keyboard to tone generator connection) and the sound
of the software or MIDI instrument. This is why the keyboard must be separated from its
own internal sound generator.
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Chapter 2
Setting Up Your System