Boss Audio Systems GT-6B Appendices, About Midi, How Midi messages are transmitted and received

Appendices

About MIDI

MIDI is an acronym for Musical Instrument Digital Interface, and is a world-wide standard for allowing electronic musical equipment to communicate by transmitting messages such as performance information and sound selections. Any MIDI equipped device is able to transmit applicable types of data to another MIDI equipped device, even if the two devices are different models or were made by different manufacturers. In MIDI, performance information such as playing a key or

fig.11-102

Broadcasting

Station A

Broadcasting

Station B

Broadcasting

Station C

T.V. information from many different broadcasting station is sent through an antena.

Select the channel of the broadcasting station you wish to watch

pressing a pedal are transmitted as MIDI Messages.

How MIDI messages are transmitted and received

First, we will explain briefly how MIDI messages are transmitted and received.

MIDI connectors

The following types of connector are used to convey MIDI messages. MIDI cables are connected to these connectors as needed.

fig.11-101

MIDI IN: This connector receives messages from another MIDI device.

MIDI OUT: This connector transmits messages from this device.

MIDI THRU: This connector re-transmits the messages that were received at MIDI IN.

*The GT-6B features both “MIDI IN” and “MIDI OUT” connectors.

MIDI channels

MIDI is able to independently control more than one MIDI device over a single MIDI cable. This is possible because of the concept of MIDI channels.

The idea of MIDI channels is somewhat similar to the idea of television channels. By changing channels on a television set, you can view a variety of programs. This is because the information of a particular channel is received when the channels of the transmitter and receiver match.

MIDI has sixteen channels 1 – 16, and MIDI messages will be received by the instrument (the receiving device) whose channel matches the channel of the transmitter.

*If omni mode is on, data of all MIDI channels will be received regardless of the MIDI channel setting. If you do not need to control a specific MIDI channel, you may set Omni On.

Main types of MIDI message used by the GT-6B

MIDI includes many types of MIDI messages that can convey a variety of information. MIDI messages can be broadly divided into two types; messages that are handled separately by MIDI channel (channel messages), and messages that are handled without reference to a MIDI channel (system messages).

Channel messages

These messages are used to convey performance information. Normally these messages perform most of the control. The way in which a receiving device will react to each type of MIDI message will be determined by the settings of the receiving device.

Program change messages

These messages are generally used to select sounds, and include a program change number from 1 to 128 which specifies the desired sound.

Control change messages

These messages are used to enhance the expressiveness of a performance. Each message includes a controller number, and the settings of the receiving device will determine what aspect of the sound will be affected by control change messages of a given controller number.

The specified parameters can be controlled with the GT-6B.

Appendices

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