Clocks & tempo

Three clocks run at once, picture time, sound time and musical time, so work can lock to frames, to audio, or to the beat.

Frames, audio samples and musical beats do not divide evenly into one another, so they are kept on separate clocks. Each node reads the clock its job requires, without you selecting one.

The clocks matter directly when you are scoring to music, locking to a live audio source, or syncing to other gear.

The three clocks

ClockRuns inUsed by
VisualFrames (24 / 30 / 60 fps)Animation, fields, anything you see
AudioAudio samples (e.g. 48,000 a second)Synths, DSP, anything you hear
MusicalBeats and bars at a tempoSequencers, tempo-synced LFOs, beat-driven motion

Visual time can run backwards: you can scrub or seek into negative frames. Audio time only moves forward. Musical time is measured in beats and bars at whatever tempo is currently set.

The three never bleed into each other. Turning beats into seconds, or samples into frames, is a deliberate exact conversion, so nothing lands roughly in time.

If a beat-synced effect feels a hair off, check the tempo bus before nudging keyframes. The fix is usually a clean tempo source rather than hand-tuning.

The tempo bus

The Musical clock does not carry its own tempo. It reads the tempo bus, a single switch that selects one tempo source at a time and feeds it to everything beat-aware in the project. Change the source once and every tempo-synced node follows.

SourceWhen to use it
ManualThe default. You set the BPM. Self-contained pieces and rehearsal.
Tap TempoPress Cmd+T in time and the tempo is read from your taps. Matching a track by ear when its BPM is unknown.
Ableton LinkTempo and phase shared with Ableton Live and other Link-enabled apps on the network. Playing alongside a DJ or producer.
MIDI ClockTempo over MIDI from a drum machine, groovebox, or DAW. Not connected yet.
MTC (MIDI Time Code)A timeline position from external gear. Not connected yet.
CLAP HostThe transport of the host application, when DNA is running as an audio plugin. Not connected yet.

The source is set on the Score node, and only one is active at a time. Switching is instant, so you can rehearse on Manual and flip to Ableton Link on joining a live set.

The last three go nowhere. MIDI Clock and MTC are decoded but never fed: nothing counts the MIDI clock tick, because the MIDI parser discards system real-time bytes before they reach anything, and the timecode reader returns no tempo by design, since timecode carries position rather than tempo. CLAP Host does not even have a reader on the bus, so a project running as a plugin does not pick up the host's tempo. Selecting any of the three leaves the clock holding its last known tempo. Use Ableton Link or a tapped tempo. Tempo sync has the detail.

Ableton Link reaches the graph two ways. Choose it on the tempo bus and it drives the Musical clock for the whole project, so every tempo-synced node follows without any wiring. Or drop the Ableton Link node in to read the session directly: it outputs bpm, beat, phase, peers and is_playing as ordinary values you can wire anywhere.

Choosing what to lock to

Clocks mix. A common live setup animates visuals on the Visual clock while a few accent effects sync to the Musical clock over Ableton Link, so they land on the beat.

See also