A device preview plays a loop through the effect so you can hear what it does. Those loops are not recordings: each is drawn in code with oscillators, filters and noise, once per sample rate, then looped as a buffer. They live in one file, demo-sound, and each has a name.
Listen
One at a time, through the same master bus as a preview.
Drone
chordAn A minor chord that never stops: a gate or a ducker has something to open and close.
Boom bap
grooveTwo bars of boom bap at 90 BPM: drums, bass, keys and a plucked line.
Boom bap kick
kickThe kick of the boom bap alone: its key.
Ask for one by name
DEMO_SOURCES holds the sounds by name, with a title and what to listen for. renderDemoSource draws one for a sample rate and keeps it, so the same buffer comes back each time.
Usage and API: demo-sound.
How they are made
Boom bap (groove) is two bars at 90 BPM. The off-beat sixteenths are pushed back a fraction of a step, which is the swing. The snare has quiet ghost notes, the hats are harder on the beat, and each hit lands a few milliseconds early or late from a fixed sequence, so it is the same every time. A sine bass, an electric piano on two chords and a plucked line sit on top. What rings past the end is folded back into the start, so no note is cut where the loop turns.
Drone (chord) is four oscillators on an A minor chord that never stop. A signal that is never quiet by itself is what a gate has to open and close.
Boom bap has a kick to go with it, not offered in the picker: a gate or a ducker follows it.
The drum voices are the ones of Synthesis.