Chapter 9. Connecting External Midi Devices; What Is Midi; Midi Connectors; Midi Channels - Boss Dr. Rhythm DR-770 Owner's Manual

Chapter 9. Connecting External MIDI Devices

What Is MIDI?

MIDI (Musical Instrument Digital Interface) is an
international standard which provides for the exchange of
music data among electronic musical instruments and
computers. Devices that have MIDI connectors can be
connected via MIDI cable and used to transmit and receive
data.

MIDI Connectors

The DR-770 has a MIDI IN connector and a MIDI OUT
connector.
fig.109-01a
MIDI In
This connector receives data from an external MIDI device.
Connect it to the MIDI OUT connector of the external MIDI
device.
MIDI Out
This connector transmits data from the DR-770. Connect it to
the MIDI IN connector of the external MIDI device. If the
"MIDI Thru Switch" (MIDI mode setting; p. 88) is turned
ON, data received at MIDI IN will be re-transmitted without
change from MIDI OUT.

MIDI Channels

MIDI uses the concept of MIDI channels (channels 1–16),
which are somewhat analogous to television channels. Data
is received only if the MIDI channel of the receiving device
matches the MIDI channel on which the data is being
transmitted.
fig.109-02a
T.V. information from many different broadcasting station is
sent through an antena.
Broadcasting
Station A
Broadcasting
Station B
Broadcasting
Station C
If MIDI channels are set as shown below, only sound module
B will produce sound when the keyboard is played.
Select the channel of the
broadcasting station you
wish to watch
fig.109-03a
Receive Channel: 2
Sound
Module A
Receive Channel: 1
Sound
Module B
MIDI
OUT Transmit Channel: 1
MIDI Messages Used by the
DR-770
MIDI uses many different types of messages to convey a
wide range of musical information. MIDI messages can be
classified broadly into messages that are handled separately
for each MIDI channel ("channel messages"), and messages
that are handled without regard to the MIDI channel
("system messages").
Messages Handled Separately for Each
MIDI Channel (Channel Messages)
These messages are used to convey musical performance
actions.
Note Messages
The DR-770 uses these messages to convey drum
performance information. On a keyboard instrument, they
convey information about which notes are played. Note
messages include the following information.
Note Number: Data that specifies the instrument (the
number of the pad to which the instrument is
assigned)
Note On: A pad is struck
Note Off: A pad is released
Velocity: The force with which the pad was struck
The note number is a value from 0 through 127, and middle
C (C4) is 60. On the DR-770, a different note number is
assigned to each instrument of a drum kit.
This means that each note number will play a different
instrument.
NOTE
The DR-770 uses note numbers 27–81.
Program Change Messages
The DR-770 uses these messages to switch drum kits.
Control Change Messages
These messages can be used to control the overall volume of
the DR-770.
MIDI IN
MIDI THRU
MIDI IN
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