Audio Which engine is making the sound, and where it is coming out. The engine is a separate
process, so leaving the performance page never stops a note.
Engine off
Output
Device — Sample rate — Stream — Build —
Choosing the output device needs two engine verbs that do not exist yet
(list-audio-devices, set-audio-device) and a stream reopen. For now
it is set at launch: ./native/jspa-engine --device <name>, and --list-devices prints the candidates.