DigiDesign Digidesign Pro Tools 8.0, Reference Manual

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Chapter 2: Pro Tools Concepts 9
MIDI
MIDI (Musical Instrument Digital Interface) is a
communication protocol for musical instru-
ments. This industry standard enables connec-
tions between a variety of devices from different
manufacturers. Examples of MIDI-compatible
equipment include synthesizers, sound mod-
ules, drum machines, MIDI patch bays, effects
processors, MIDI interfaces, MIDI control sur-
faces, and MIDI sequencers.
MIDI devices are equipped with 5-pin DIN con-
nectors, labeled as either IN, OUT, or THRU. The
MIDI OUT port transmits messages. The MIDI
IN port receives messages. The MIDI THRU out-
puts whatever is received from the IN port. MIDI
devices are connected with MIDI cables that are
available at most music stores.
USB and FireWire-compatible MIDI devices send
and receive MIDI messages to and from the
computer over USB or FireWire.
The MIDI protocol provides 16 channels of
MIDI per port. A single MIDI cable can transmit
a separate set of messages for each of the 16
channels. These 16 channels can correspond to
separate MIDI devices or to multiple channels
within a single device (if the device is
multitim-
bral ). Each channel can control a different in-
strument sound. For example, bass on
channel 1, piano on channel 2, and drums on
channel 10. Similar to a multitrack tape re-
corder, a MIDI sequencer can record complex ar-
rangements—even using only a single multitim-
bral keyboard.
MIDI Terms
The following are some basic MIDI terms:
MIDI Instrument
A hardware MIDI device or
software instrument (such as an instrument
plug-in).
MIDI Interface
Hardware that lets computers
connect to and communicate with MIDI devices
(such as the M-Audio MIDISPORT).
MIDI Device
Any physical MIDI keyboard, sound
module, effects device, or other
equipment that can send or receive MIDI
information.
MIDI Controller
Any MIDI device that transmits
MIDI performance data. These include MIDI
keyboards, MIDI guitar controllers, MIDI wind
controllers, and others. Controllers transmit
MIDI from their MIDI OUT ports.
MIDI Control Surface
Any device (such as the
Digidesign Command|8), which uses a MIDI
connection to send control messages to a soft-
ware program, but is not generally used to
record MIDI information.
Multitimbral The ability of one MIDI device to
play several different instrument sounds (such
as piano, bass, and drums) simultaneously on
separate MIDI channels. This makes it possible
for a single multitimbral MIDI instrument to
play back entire arrangements.
MIDI signal flow
Not all devices will have all three MIDI
ports (IN, OUT, and THRU).
passes input