The MIDI controller message tells a MIDI device that at a certain time the value of some controller should change.
A controller is a slider, knob, or a switch, and hence could be a volume control, pan control, legato pedal, and others (a list of standard MIDI controllers is provided below).
This message belongs to the category of MIDI voice messages.
The MIDI controller message consists of three bytes of data. The first byte is the status byte and has hexadecimal values between 0xB0 and 0xBF. The high nibble of the status byte is B, which tells the MIDI device that this is a "controller" message. The low nibble of the status byte is between 0 and F (0 and 15 in decimal values) and points to one of the 16 MIDI channels. Two bytes follow the status byte. The first byte after the status byte is has values between 0x00 and 0x7F (0 and 127 in decimal values) and identifies the controller that should be affected (see below). A value of 0x07, for example, signifies that this is a coarse volume controller. The second byte after the status byte carries the value that the controller should receive. What the value means depends on the MIDI device.
The following is an example of a MIDI controller message.
0xB6 0x07 0x10
The status byte 0xB6 shows that this is a controller message for channel 6. The controller is 0x07, which is a coarse volume controller. This volume should be set to 0x10.
The following is a list of defined standard controllers. The last column shows whether these controllers are required for compliance with the standard General MIDI 1 (GM1) or General MIDI 2 (GM2). "Coarse" and "fine" should be interpreted as the most significant bits (MSB) and least significant bits (LSB) of controller values that can be sent in pairs to form 14-bit values, after the top-most bit of each controller value byte is dropped.
|Hexadecimal value||Decimal value||Controller||Values||Required by|
|0x00||0||Bank select (coarse)||0-127||GM21|
|0x01||1||Modulation wheel (coarse)||0-127||GM1, GM2|
|0x02||2||Breath controller (coarse)||0-127|
|0x04||4||Foot controller (coarse)||0-127|
|0x05||5||Portamento time (coarse)||0-127||GM2|
|0x06||6||Data entry (coarse)||0-127||GM1, GM2|
|0x07||7||Channel volume (coarse) (formerly main volume)||0-127||GM1, GM2|
|0x0A||10||Pan (coarse)||0-127||GM1, GM2|
|0x0B||11||Expression (coarse)2||0-127||GM1, GM2|
|0x0C||12||Effect control 1 (coarse)||0-127|
|0x0D||13||Effect control 2 (coarse)||0-127|
|0x10||16||General purpose controller 1 (coarse)||0-127|
|0x11||17||General purpose controller 2 (coarse)||0-127|
|0x12||18||General purpose controller 3 (coarse)||0-127|
|0x13||19||General purpose controller 4 (coarse)||0-127|
|0x20||32||Bank select (fine)||0-127||GM2|
|0x21||33||Modulation wheel (fine)||0-127|
|0x22||34||Breath controller (fine)||0-127|
|0x24||36||Foot controller (fine)||0-127|
|0x25||37||Portamento time (fine)||0-127|
|0x26||38||Data entry (fine)||0-127||GM1, GM2|
|0x27||39||Channel volume (fine) (formerly main volume)||0-127|
|0x2C||44||Effect control 1 (fine)||0-127|
|0x2D||45||Effect control 2 (fine)||0-127|
|0x40||64||Hold (damper, sustain) pedal 1 (on/off)||< 63 is off, >= 64 is on||GM1, GM2|
|0x41||65||Portamento pedal (on/off)||< 63 is off, >= 64 is on||GM2|
|0x42||66||Sostenuto pedal (on/off)||< 63 is off, >= 64 is on||GM2|
|0x43||67||Soft pedal (on/off)||< 63 is off, >= 64 is on||GM2|
|0x44||68||legato pedal (on/off)||< 63 is off, >= 64 is on|
|0x45||69||Hold pedal 2 (on//off)||< 63 is off, >= 64 is on|
|0x46||70||Sound controller 1 (default is sound variation)||0-127|
|0x47||71||Sound controller 2 (default is timbre / harmonic intensity / filter resonance)||0-127||GM2|
|0x48||72||Sound controller 3 (default is release time)||0-127||GM2|
|0x49||73||Sound controller 4 (default is attack time)||0-127||GM2|
|0x4A||74||Sound controller 5 (default is brightness or cutoff frequency)||0-127||GM2|
|0x4B||75||Sound controller 6 (default is decay time)||0-127||GM2|
|0x4C||76||Sound controller 7 (default is vibrato rate)||0-127||GM2|
|0x4D||77||Sound controller 8 (default is vibrato depth)||0-127||GM2|
|0x4E||78||Sound controller 9 (default is vibrato delay)||0-127||GM2|
|0x4F||79||Sound controller 10 (default is undefined)||0-127|
|0x50||80||General purpose controller 5||0-127|
|0x51||81||General purpose controller 6||0-127|
|0x52||82||General purpose controller 7||0-127|
|0x53||83||General purpose controller 8||0-127|
|0x58||88||High resolution velocity prefix||0-127|
|0x5B||91||Effect 1 depth (default is reverb send level, formerly external effect depth)||0-127||GM2|
|0x5C||92||Effect 2 depth (formerly tremolo depth)||0-127|
|0x5D||93||Effect 3 depth (default is chorus send level, formerly chorus depth)||0-127||GM2|
|0x5E||94||Effect 4 depth (formerly celeste depth)||0-127|
|0x5F||95||Effect 5 depth (formerly phaser level)||0-127|
|0x60||96||Data button increment|
|0x61||97||Data button decrement|
|0x62||98||Non-registered parameter (coarse)||0-127|
|0x63||99||Non-registered parameter (fine)||0-127|
|0x64||100||Registered parameter (coarse)||0-127||GM1, GM2|
|0x65||101||Registered parameter (fine)||0-127||GM1, GM2|
|0x78||120||All sound off||0|
|0x79||121||All controllers off||0||GM1, GM2|
|0x7A||122||Local control (on/off)||0 off, 127 on|
|0x7B||123||All notes off||0||GM1, GM2|
|0x7C||124||Omni mode off||0|
|0x7D||125||Omni mode on||0|
|0x7E||126||Mono operation and all notes off|
|0x7F||127||Poly operation and all notes off||0|
1 The MIDI Manufacturer's Association (MMA) specifies that some GM2 controllers are optional. It is not clear which ones are optional and which ones are required.
2 The expression controllers (coarse expression 0x0B and fine expression 0x2B) are typically used for expression of music dynamics. Expressions in music can refer to tempo (e.g., andante), dynamics (e.g., crescendo), style (e.g., furioso), or articulation (e.g., staccato), but here the controllers are for dynamics (i.e., volume). Thus, they work similarly to controllers for volume (e.g., 0x07). By convention though, a volume controller on a MIDI device would be a knob and would be used for setting the volume level for the song throughout. An expression controller could be a pedal and would be used to modify the volume during the song.
How a MIDI device would respond to a controller depends on the device. For controllers between 0x01 and 0x1F and between 0x40 and 0x5F, with the General MIDI 2 standard, the MIDI controller destination message was defined to help standardize device response to these controllers (and the channel pressure and key pressure messages).