`synth()` — Web Audio Synth Cue

The synth() cue creates a lightweight Web Audio sound source inside Oscilla. It is intended for reference tones, drones, textures, chords, and simple patterned sound processes, integrated directly into the score timeline.

The design prioritises:

deterministic, cue-scoped behaviour
readable parameter syntax
low default amplitudes and click-free envelopes
optional pattern sequencing
optional OSC mirroring

The synth is not intended as a full synthesiser environment. For full electroacoustic work, Oscilla is designed to operate in conjunction with external audio systems via OSC (e.g. SuperCollider, Pure Data, Max). The built-in synth provides a bounded, score-aligned sound source intended for rehearsal contexts away from a complete setup, as well as for simple tone cues, drones, and basic animation- or pattern-driven sound sequences embedded directly in the score.

Basic Usage

synth(uid:refA, wave:sine, freq:440, amp:0.1)

Pitch may be specified as Hz or note name:

synth(uid:tuning, wave:sine, freq:A4, amp:0.08)

Wave Types

The following wave values are supported:

sine
square
saw
triangle
noise

Oscillator waveforms map directly to standard Web Audio oscillator types.

noise produces a broadband noise source generated from a looping audio buffer. No spectral colouring is applied.

Lifetime and Duration

Region-based lifetime (default)

When synth() is attached to a cue element, the synth starts when the playhead enters the cue’s bounding box and stops when the playhead exits it.

synth(uid:regionTone, wave:sine, freq:220, amp:0.06)

Explicit duration

synth(uid:fixedDur, wave:sine, freq:220, dur:5, amp:0.07)

The synth stops automatically after the specified number of seconds.

Persistent process lifetime

synth(uid:persist, wave:saw, freq:110, lifetime:process, amp:0.05)

The synth continues until explicitly stopped.

Amplitude Envelope (ADSR)

synth(
  uid:env1,
  wave:saw,
  freq:220,
  amp:0.12,
  env:{a:0.5, d:0.2, s:0.7, r:1.2}
)

Envelope parameters:

a — attack (seconds)
d — decay (seconds)
s — sustain level (0–1)
r — release (seconds)

Chords

If freq is an array, multiple oscillators are created and summed as a chord.

synth(
  uid:pad3,
  wave:sine,
  freq:[440, 477, 644, 777],
  env:{a:1.5},
  amp:0.12
)

All voices share the same envelope and effects chain.

Patterned Parameters

The following parameters may be static values, arrays, or pattern functions:

freq
amp
dur
filter.freq
filter.q
pan

Frequency sequence

synth(
  uid:seq1,
  wave:triangle,
  freq:Pseq(220, 330, 440),
  dur:Pseq(1, 1, 2),
  amp:0.08
)

Patterned chord progression

synth(
  uid:chordSeq,
  wave:saw,
  freq:Pseq(
    [220, 330, 440],
    [247, 370, 494],
    [196, 294, 392]
  ),
  dur:1.5,
  amp:0.1
)

Random pitch

synth(
  uid:randFreq,
  wave:square,
  freq:Prand(200, 400, 600),
  dur:0.8,
  amp:0.09
)

Filters

synth(
  uid:filterSeq,
  wave:saw,
  freq:330,
  filter:{type:lp, freq:Pseq(400, 800, 1600, 800), q:0.7},
  dur:0.5,
  amp:0.08
)

Supported filter types:

lp
hp
bp
notch

Delay

synth(
  uid:delayLead,
  wave:square,
  freq:550,
  delay:{time:0.25, fb:0.35, mix:0.2},
  amp:0.12
)

Reverb

synth(
  uid:revDrone,
  wave:sine,
  freq:110,
  reverb:{mix:0.3, time:2, damp:3000},
  amp:0.07
)

Glide (Frequency Only)

synth(
  uid:glide1,
  wave:sine,
  freq:Pseq(220, 330, 440),
  glide:0.1,
  dur:1,
  amp:0.1
)

glide specifies the time (seconds) used to interpolate frequency changes between steps. It applies only to pitch.

Interpolation Mode

synth(
  uid:stepSeq,
  wave:triangle,
  freq:Pshuf(300, 450, 600),
  interp:step,
  dur:1,
  amp:0.08
)

interp:smooth — ramps between values
interp:step — immediate value changes

Pan

synth(
  uid:panTest,
  wave:sine,
  freq:440,
  pan:-0.6,
  amp:0.09
)

Pan may be static or patterned but does not support continuous modulation.

OSC Mirroring

synth(
  uid:oscLead,
  osc:1,
  oscAddr:/synth/lead,
  wave:saw,
  freq:440,
  amp:0.1
)

Stopping a Synth

synthStop(uid:seq1, rel:0.5)

The optional rel parameter specifies release time in seconds.

Summary

The synth() cue provides a bounded, score-aligned sound source suitable for reference tones, drones, chords, and simple patterned textures. All behaviour is deterministic and cue-scoped, and integrates directly with Oscilla’s timing and animation model.

synth() — Web Audio Synth Cue