MIDI provides sixteen channels (1—16). When the channel which the sending device
(the master) is using to transmit on matches the channel which the receiving device (the
slave) is using to receive on, the performance data is conveyed. When the MIDI chan-
nels are set as illustrated below and you play the keyboard, sound will be produced only
by sound module B. Sound module A will not sound. This is because only sound mod-
ule B is set to receive on the same channel that the keyboard is using to transmit on.
Sound module A’s channel doesn’t match, so it won’t sound.
The SCB-55 is capable of simultaneously recognizing the MIDI messages on all 16 chan-
nels. In other words, it is capable of playing 16 different Parts at the same time. Of these,
the Part which is set to receive on MIDI channel 10 is known as the Drum Part. This Part
provides a collection of percussive instrument sounds, with a different sound for each
Note Number (p. 19). The other Parts, those having a MIDI receive channel from 1-9 or
11-16, are known as Standard Parts, and are used for melody or bass, chords, etc.
Sound modules such as the SCB-55 are multi-timbral, which means they can simultane-
ously receive data on a multiple number of MIDI channels, and can play the musical
data for a number of Parts simultaneously.
(2) MIDI Messages Handled by the SCB-55
Various types of MIDI messages are used to convey a musical performance.
Channel messages are used to convey musical actions, such as “how hard a key was
struck” (converted into a data format called a MIDI message). The action the device
takes (how to produce the sound, etc.) when each MIDI message is received will depend
on the specifications of the device. If the function requested by a message is not includ-
ed in the device, the desired effect may not be achieved.
* MIDI messages required for responding to General MIDI System Level 1 specifications
are marked with a
✩
.
Note Messages
✩
These messages convey what is played on a keyboard or other instrument. The types of
Note messages are as follows:
Note Number:
A number representing the position of a key on a keyboard.
Note On:
Indicates that a key has been pressed.
Note Off:
Indicates that a key has been released.
Note On Velocity:
The strength with which a key has been pressed.
Note Numbers range from 0—127 and correspond with the positions of keys on a key-
board. Middle C (C4) is number 60. In the Drum Part, a different percussive instrument
sound is assigned to each Note Number.
Pitch Bend Change
✩
This message conveys the operation of the bender lever (or pitch bend wheel) that is
found on many synthesizers. The pitch will change when this message is received.
MIDI OUT
MIDI IN
MIDI THRU
MIDI IN
Transmit Channel : 1
Receive Channel : 2
Receive Channel : 1
Sound Module A
Sound Module B
. .
SOUND
Canvas
. .
SOUND
Canvas
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