Transport & Tempo

Starting and stopping playback, setting the BPM, and how loop lengths work per instrument.

The transport is the track's clock. It drives every instrument's playhead, the metronome and the scene system, and it is controlled from the bar across the top of the app.

Play and stop

Press the spacebar to start and stop playback. The shortcut works from anywhere in the app and does exactly the same thing as the play/stop button in the transport bar.

Note: Browsers block audio until you interact with the page. The first spacebar press both unlocks the browser's audio engine and starts the transport, so occasionally the very first press feels like it only did half the job.

Tempo (BPM)

The BPM readout in the transport bar is click-to-edit. Tempo can be set between 40 and 240 BPM.

Tempo is a property of the whole track, shared by every instrument, and it is part of the saved document — so it persists across reloads and syncs live to collaborators.

Changing tempo while playing

You can change the BPM mid-playback. Because the sequencer schedules notes slightly ahead of time to keep timing rock-solid, a tempo change takes effect a fraction of a second later rather than instantaneously. In practice it sounds immediate.

Loop length

Loop length is set per instrument, not globally, from the BEATS control in the editor toolbar. The options are 4, 8, 16, 32 and 64 beats.

This is one of the more musically useful things in the app. Because each instrument loops independently, a 4-beat drum pattern running against a 6- or 16-beat melodic part produces a phrase that takes several bars to repeat, without you having to write out the variation by hand.

Loop length is read fresh on every beat, so changing it takes effect within the loop that is currently playing rather than waiting for the next cycle.

The transport bar

Alongside play/stop and the tempo, the bar carries the track title (click to rename), the track switcher, the save button, and the metronome and MIDI toggles.

Note: Some readouts in the transport bar — the signature and bar displays, and the previous-track and record buttons — are visual only at present and are not yet wired to behaviour.

Where to go next