MIDI Machine Control (MMC)

A part of the MIDI spec that allows MIDI devices to control hardware devices, MIDI Machine Control is commonly used to send transport control messages to hardware recorders. Play, Stop, and Locate are examples of MMC messages. Note that MMC does not include synchronization information, although MIDI sync info could also be sent to/from the device that MMC is addressing. MMC allows you to centralize control of your studio from a MIDI source (often a sequencer). A common scenario: Pressing play on a MIDI seqencer sends an MMC play message to a connected multitrack recorder, which begins playing. As the deck plays, it generates MIDI Time Code (MTC) which the sequencer then synchronizes to (chases). When “stop” is pressed on the sequencer, the deck also stops, and ceases to send out MTC. When MTC stops, the sequencer stops chasing. Locating to a point within the sequence will cause the deck to fast forward or rewind to the corresponding location on tape.