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MIDI clock

MIDI clock plays drum machines, grooveboxes, synths with arpeggiators and other apps in time with your mix. Most hardware follows MIDI clock rather than Ableton Link.

Pick where the clock goes

Open Settings › Controllers and find MIDI Clock at the bottom.

  1. Press + beside Add output and pick the MIDI output your gear is on (a MIDI interface, or the gear itself over USB).
  2. To reach another app on the same computer, pick openDJ Clock (other apps) (macOS and Linux) and choose openDJ Clock as the MIDI clock input in that app.
  3. Add as many outputs as you like. × takes one away.

If the gear plays a little early or late against the music, move its Offset: + when it plays early, − when it plays late, up to 50 ms either way.

Turn it on

Open the MASTER button in the top bar and turn on MIDI Clock. CLOCK shows on the MASTER button while it's on.

The clock follows the master deck, the same deck Link follows: the deck that's playing, or the one started first while both play. It runs at that deck's tempo, 24 pulses a beat, and stays on its beat.

  • When the master deck starts, the clock sends Start on its next downbeat, so pattern-based gear begins on bar 1 with the music. Cue to a bar and press PLAY to start them together.
  • If the gear loses the bar (you jumped in the track, or the other deck took over), press RESTART ON BAR: the gear starts again on the master deck's next downbeat, without stopping before.
  • When the decks stop, the clock sends Stop and carries on at the last tempo, so the gear keeps showing it. To keep the gear playing instead, turn on Keep running when the decks stop in Settings › Controllers.

On Windows only one app at a time can open a MIDI output, so close other apps using it first.

The decks can follow the gear instead of leading it.

  1. In Settings › Controllers › MIDI Clock, pick the gear's MIDI output as the Clock input.
  2. In the MASTER panel, set SYNC follows to Clock. The tempo coming in shows under it.
  3. Turn on SYNC on the decks that should follow.

Synced decks play at the clock's tempo. Once the gear has sent Start they land on the same beat of its bar, so your downbeats fall on its bar 1. A jittery hardware clock is smoothed, so the decks don't wobble with it; a real tempo change is followed within two beats.

To follow another app or a live act in an Ableton Link session instead, set SYNC follows to Link (this turns Link on). openDJ then joins the session's tempo and bars rather than leading it. Deck goes back to the decks leading, as usual.

While the decks follow Link or a clock, MIDI clock out passes on that tempo.