MIDIsync

MIDIsync refers to a set of techniques and standards used to coordinate timing and tempo between MIDI devices and software. The term is not a single, formal standard, but a shorthand for how devices stay in rhythm during playback. The core mechanisms in traditional MIDIsync include MIDI Clock, MIDI Time Code (MTC), and MIDI Machine Control (MMC). MIDI Clock transmits timing pulses at a rate derived from the set tempo; a master device sends 24 pulses per quarter note to synchronize slaves. MTC carries SMPTE-compatible time information, enabling precise alignment of devices on a timeline. MMC sends transport commands like play, stop, rewind to control playback across devices.

In practice, the master device sets tempo and timing mode; slaves follow the MIDI Clock or MTC. This is commonly used when syncing a hardware sequencer or drum machine to a computer-based DAW, or when coordinating multiple hardware synths during a live performance. Some setups rely solely on MIDI Clock, while others mix Clock with MTC for position accuracy.

Limitations include clock drift, jitter, and the fact that MIDI is not designed for high-precision timing compared to audio. To address these issues, many modern workflows use DAW-based synchronization, clock-sharing over USB/MIDI, or alternative protocols like Ableton Link or OSC for tempo transmission, though these may not use MIDI Clock.

MIDIsync remains foundational in environments where hardware devices must be tempo-aligned, even as workflows diversify.