Simple, blocking note/beat playback built directly on AudioEngine — no transport control (play/pause/stop), no position tracking, just "turn this on, sleep, turn it off" for as many beats as given. Used where a single synchronous sequence needs to be auditioned (e.g. previewing a track in isolation); full Song playback with pause/resume/seek instead goes through Termtab.Audio.PlaybackThread, which reuses durationToMicroseconds from here for its own timing.