Instruments

Every field is optional. With none, an instrument is a soft square-wave lead.

Field	Default	Meaning
wave	"square"	"sine", "square", "sawtooth", "triangle", or "noise" for drums.
attack	0.005	Seconds to reach full volume.
decay	0.1	Seconds to fall to the sustain level.
sustain	0.6	Level held while the note lasts, 0 to 1.
release	0.08	Seconds to fade after the note ends.
volume	0.3	Loudness, 0 to 1. Accented hits play louder.
octave	0	Shift every note up or down by whole octaves.
detune	none	Add a second oscillator this many cents apart, for a thicker, chorused sound.
filter	none	A low-pass filter: { cutoff, q, sweep }. cutoff in Hz, q is resonance, and sweep opens the filter this many Hz higher at the start of each note, then closes it over the decay.
drop	none	Start each note this many semitones higher and slide down to it. Kicks and "bloop" sounds.
vibrato	none	Wobble the pitch by this many cents, 5.5 times a second.
echo	none	Send this much (0 to 1) to a shared echo, timed to the song (a dotted eighth).
reverb	none	Send this much (0 to 1) to a shared room reverb.
pan	0	Stereo position, -1 (left) to 1 (right).

The master bus

Everything a player makes goes through a gentle compressor, which glues the parts together, and then a limiter, so the mix never clips however many notes pile up. If your engine already masters its audio, turn it off: new Player({ master: false }).

Recipes

const instruments = {
  // Bouncy chiptune lead with a little space around it.
  lead: { wave: "square", decay: 0.14, sustain: 0.35, volume: 0.13, echo: 0.28, vibrato: 6 },

  // Squelchy bass: a resonant filter that sweeps shut on every note.
  bass: { wave: "sawtooth", octave: -1, decay: 0.18, sustain: 0.4, volume: 0.22, filter: { cutoff: 380, q: 9, sweep: 1400 } },

  // Warm chords under everything.
  pad: { wave: "triangle", attack: 0.15, decay: 0.4, sustain: 0.5, release: 0.4, volume: 0.06, detune: 8 },

  // Drums.
  kick: { wave: "sine", drop: 24, decay: 0.12, sustain: 0, volume: 0.5 },
  snare: { wave: "noise", decay: 0.08, sustain: 0, volume: 0.12, filter: { cutoff: 2200, q: 3 } },
  hat: { wave: "noise", decay: 0.03, sustain: 0, volume: 0.08, filter: { cutoff: 9000 } },

  // A cartoon "bloop": a sine that drops into each note.
  bloop: { wave: "sine", drop: 7, decay: 0.12, sustain: 0.2, volume: 0.25 },
};

Keep the total quiet: several instruments at full volume clip. Leads around 0.1 to 0.2, bass around 0.2, drums and pads lower.