What is MIDI?

Finally, we’ll take a look at the actual data that gets recorded and that serves as the basis for playing the sounds. For example, let’s say you play a “C” quarter note using the grand piano sound on the instrument’s keyboard. Unlike an acoustic instrument that puts out a resonated note, the electronic instrument puts out information from the keyboard such as “with what voice,” “with which key,” “about how strong,” “when was it pressed” and “when was it released.” Then each piece of information is changed into a number value and sent to the tone generator. Using these numbers as a basis for sound generation, the tone generator plays the stored sampled note.

Example Keyboard Data

Voice number (with what voice)

01

(grand piano)

 

 

 

Note number (with which key)

60

(C3)

 

 

Note on (when was it pressed)

Timing expressed

and

numerically

note off (when was it released)

(quarter note)

 

 

Velocity

120 (strong)

(strength at which it was played)

 

 

 

 

 

Panel operations on the instrument, such as playing the keyboard and selecting voices, are processed and stored as MIDI data. The auto accompaniment Styles and Songs also consist of MIDI data.

MIDI is an acronym that stands for Musical Instrument Digital Interface, which allows electronic musical instruments to communicate with each other, by sending and receiving compatible Note, Control Change, Program Change and various other types of MIDI data, or messages.

The instrument can control a MIDI device by transmitting note related data and various types of controller data. The instrument can be controlled by incoming MIDI messages which automatically determine the tone generator mode, select MIDI channels, voices and effects, change parameter values and of course play the voices specified for the various parts.

n

MIDI data has the following advantages over audio data:

•The amount of data is much less.

•The data can be effectively and easily edited, even to the point of changing voices and transforming the data.

MIDI messages can be divided into two groups: Channel messages and System messages.

Channel Messages

The PSR-OR700 is an electronic instrument that can handle 16 MIDI channels (or reception of 32 channels for MIDI data reception when using the [USB] termi- nal). This is usually expressed as “it can play 16 instruments at the same time.” Channel messages transmit information such as Note ON/OFF, Program Change, for each of the 16 channels.

Message Name

Operation/Panel Setting

 

 

Note ON/OFF

Messages which are generated when

 

the keyboard is played. Each mes-

 

sage includes a specific note num-

 

ber which corresponds to the key

 

which is pressed, plus a velocity

 

value based on how hard the key is

 

played.

 

 

Program Change

For selecting Voices (with control

 

change bank select MSB/LSB set-

 

tings)

 

 

Control Change

Volume, panpot (Mixing Console),

 

MODULATION Wheel operation

 

etc.

 

 

Pitch Bend

PITCH BEND Wheel operation

 

 

n

The performance data of all Songs and Styles is handled as MIDI data.

MIDI Channels

MIDI performance data is assigned to one of sixteen MIDI channels. Using these channels, 1–16, the performance data for sixteen different instrument parts can be simultaneously sent over one MIDI cable.

Think of the MIDI channels as TV channels. Each TV station transmits its broadcasts over a specific channel. Your home TV set receives many different programs simultaneously from several TV stations and you select the appropriate channel to watch the desired program.

Weather report

NEWS2

1

NEWS

2

MIDI operates on the same basic principle. The transmitting instrument sends MIDI data on a specific MIDI channel (MIDI Transmit Channel) via a single MIDI cable to the receiving instrument. If the receiving instru- ment’s MIDI channel (MIDI Receive Channel) matches the Transmit Channel, the receiving instrument will sound according to the data sent by the transmitting instrument.

 

MIDI

 

MIDI Transmit channel 2

cable

MIDI Receive channel 2

 

n

The instrument’s keyboard and internal tone generator are also connected by MIDI. → LOCAL CONTROL (page 180)

For example, several parts or channels can be transmitted simultaneously, including the Style data (as shown on the next page).

with Instrument Your Using Devices Other

PSR-OR700 Owner’s Manual 175