MIDI System Exclusive message

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A MIDI event that carries the MIDI system exclusive message, also known as a "MIDI sysex message", carries information that is specific to the manufacturer of the MIDI device receiving the message. The action that this message prompts for can be anything.

A manufacturer, such as Lexicon, for example, could send a message that only Lexicon devices will understand and other devices will simply ignore.

This message belongs to the category of MIDI system common messages.

The MIDI system exclusive message consists of virtually unlimited bytes of data. The first byte is the status byte and has the hexadecimal value 0xF0. The second byte is the manufacturer ID. Various MIDI device manufacturers have assigned IDs and those IDs are used in the system exclusive message so that the devices produced by those manufacturers know that the system exclusive message should be acted upon (if the message is from the right manufacturer) or ignored (if the message is from another manufacturer). A list of assigned manufacturer IDs is provided below. Several (unlimited number) of bytes of data will follow the manufacturer ID. The one common thing among these bytes of data is the fact that the top bit of each byte is 0, and thus these bytes can only carry values between 0x00 and 0x7F (0 and 127). The last byte of the message is 0xF7 and signifies the end of the message. When encountering this last byte MIDI devices that are from different manufacturers and do not understand the message will know when the message ends.

The following is an example of a MIDI "system exclusive" message.

0xF0 0x41 0x01 0x34 0xF7

The status byte 0xF0 shows that this is a system exclusive message. The manufacturer ID is 0x41 which shows that this is a Roland system exclusive message. The data of the message is 0x01 0x34, which prompts the Roland device to do something (this is only an example and such a Roland message probably does not actually exist). The 0xF7 byte shows that the message is finished.

Note that, since all bytes in the data portion after the manufacturer ID and before 0xF7 must have a top bit of 0, any status byte that comes after the manufacturer ID will be interpreted by devices that do not understand the message as the end of the message (since status bytes have a top bit of 1).

The following is a list of assigned manufacturer IDs.

Hexadecimal value Decimal value Manufacturer
0x01 1 Sequential Circuits
0x02 2 Big Briar
0x03 3 Octave / Plateau
0x04 4 Moog
0x05 5 Passport Designs
0x06 6 Lexicon
0x07 7 Kurzweil
0x08 8 Fender
0x09 9 Gulbransen
0x0A 10 Delta Labs
0x0B 11 Sound Comp.
0x0C 12 General Electro
0x0D 13 Techmar
0x0E 14 Matthews Research
0x10 16 Oberheim
0x11 17 PAIA
0x12 18 Simmons
0x13 19 Gentle Electric
0x14 20 Fairlight
0x15 21 JL Cooper
0x16 22 Lowery
0x17 23 Lin
0x18 24 Emu
0x1B 27 Peavey
0x20 32 Bon Tempi
0x21 33 S.I.E.L.
0x23 35 SyntheAxe
0x24 36 Hohner
0x25 37 Crumar
0x26 38 Solton
0x27 39 Jellinghous Ms
0x28 40 CTS
0x29 41 PPG
0x2F 47 Elka
0x40 64 Kawai
0x41 65 Roland
0x42 66 Korg
0x43 67 Yamaha
0x44 68 Casio
0x45 69 Akai

A manufacturer can obtain an ID from the International MIDI Association. Otherwise the manufacturer has two alternative options of defining his own system exclusive message. First, one can use a manufacturer ID that is specifically reserved for educational and development purposes. This ID, however, should not be used for commercial purposes. This ID is 0x7D. Second, one can use someone else’s ID as long as the format of the system exclusive message is used as it is and without changes.

Universal system exclusive messages

There are two universal IDs that can be used by system exclusive messages instead of the specific manufacturer IDs above. Since these two IDs are not specific to a manufacturer, but universal, all MIDI devices should consider responding to those. These IDs are as follows.

Hexadecimal value Decimal value Description
0x7E 126 Real time
0x7F 127 Non-real time

In other words, 0x7F is carried by system exclusive messages to which all MIDI devices should respond to in real time (immediately) and 0x7E is carried by system exclusive messages to which all MIDI devices will respond to, but not in real time (not necessarily immediately). For example, the MIDI full frame message is a system exclusive message with manufacturer ID 0x7F. This message prompts all MIDI devices to immediately cue up to a certain point in time.

The first byte after the real time / non-real time ID is the "system exclusive channel". Normal system exclusive messages do not have a channel, but universal system exclusive messages do have a channel that could be from 0x00 to 0x7F (from 0 to 127). Normally, the system exclusive channel will actually be the manufacturer ID in the table above (e.g., 0x41 for Roland), so that the message can be sent to a specific MIDI device. If the system exclusive channel is 0x7F then this message is for all MIDI devices.

The two bytes after the system exclusive channel are sub-IDs and describe what the message is about. For example, the two bytes “0x01 0x01” show that the message is the MIDI Full Frame message and that the rest of the data should be used to discern time to which the MIDI device should cue.

Examples of universal MIDI system exclusive messages include the MIDI master volume message, the MIDI full frame message, and the general MIDI system enable / disable message.

See also:
Musical Instrument Digital Interface (MIDI)

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