| name | strudel-effects |
| description | Reference for every filter, modulation, and pattern effect in Strudel — the "weird stuff" toolbox. Use when a track sounds flat and needs movement, distortion, granular texture, or character. Organised by category, with idiomatic usage and what each effect *actually does to your ear*. |
Strudel exposes the full Web Audio + custom DSP chain. Most "flat sounding" tracks aren't missing voices — they're missing movement and weight on existing voices. Reach for these.
Filters
| Method | Effect | Idiom |
|---|
.lpf(N) | low-pass cutoff (Hz) | lpf(sine.range(200, 1500).slow(16)) slow filter sweep |
.hpf(N) | high-pass cutoff | hpf(3000) thin out a hi-hat to just the click |
.bandf(N) | bandpass center | telephone-voice on vocals |
.lpq(N) / .hpq(N) | resonance (0–30+) | lpf(800).lpq(8) self-oscillating filter scream |
.lpenv(N) | filter envelope amount | env opens filter on attack |
.lpattack(N) / .lpdecay(N) / .lprelease(N) | filter env ADSR | shape the open-shut motion |
Recipe — Bonobo lush pad: .lpf(sine.range(400, 1200).slow(20)) — slow breathing filter, 20-cycle sweep.
Reverb / space
| Method | Effect |
|---|
.room(0–1) | reverb send wet amount |
.roomsize(N) | room size (small → cathedral) |
.roomlp(N) | low-pass on reverb tail |
.roomdim(N) | dim/dampen reverb |
.ir("hall") | impulse-response reverb (named IRs) |
Recipe — Kiasmos cathedral strings: .room(0.95).roomsize(15).roomlp(2000) — huge but rolled off so not muddy.
Delay (echo)
| Method | Effect |
|---|
.delay(0–1) | wet send |
.delaytime(N) | seconds per echo (or 1/4 for quarter note) |
.delayfeedback(0–1) | feedback (>0.7 = chaos) |
Recipe — DJRUM dub tail: .delay(0.6).delaytime(0.625).delayfeedback(0.78) — 5/8 dotted echo, three-tap pingpong.
Distortion / saturation
| Method | Effect |
|---|
.distort(N) | hard clip distortion |
.shape(0–1) | wavefolding/shape |
.crush(N) | bitcrush (1–16 bits) |
.coarse(N) | sample rate reduction (lo-fi) |
.overgain(N) | post-gain boost (for clipping) |
Recipe — Skee Mask lo-fi grit: .crush(8).coarse(3).gain(0.4) — 8-bit, decimated, controlled.
Modulation (movement)
| Method | Effect |
|---|
.vib(N) / .vibrato(N) | pitch vibrato rate |
.tremolo(N) | amplitude tremolo |
.phaser(N) / .phasersweep(N) | phaser |
.leslie(N) | leslie speaker emulation |
.detune(N) | static or modulated detune (cents) |
Recipe — Floating Points modular drift: .detune(perlin.range(-0.15, 0.15).slow(11)) — slow random pitch drift, the "modular" feel.
Stereo
| Method | Effect |
|---|
.pan(0–1) | static pan |
.pan(sine.range(0.2, 0.8).slow(N)) | auto-pan |
.panspan(N) | per-event pan variation |
Pattern operators (the WEIRD stuff)
| Method | Effect |
|---|
.fast(N) / .slow(N) | speed/slow the pattern |
.rev() | reverse |
.palindrome() | forward then reverse |
.degradeBy(0–1) | random drop notes (0.4 = 40% drop) |
.sometimes(fn) | randomly apply fn |
.often(fn) / .rarely(fn) | weighted random apply |
.every(N, fn) | apply fn every N cycles |
.when(cond, fn) | conditional apply |
.jux(fn) | apply fn to right channel only (stereo effect) |
.off(N, fn) | apply fn to a copy offset by N |
.stutter(N) | re-trigger each event N times |
.chunk(N, fn) | divide pattern into N chunks, apply fn to one per cycle |
.ply(N) | repeat each event N times in place |
.brak() | drop every 2nd event |
.struct("1 0 1 1") | gate by external rhythm |
.mask(pattern) | gate by pattern (0/1) |
.chop(N) | slice each event into N pieces |
.striate(N) | interleaved chop |
Recipe — granular crush (Skee Mask): s("piano").chop(16).gain(perlin.range(0.05, 0.25)) — chops a piano hit into 16 tiny grains, random gain per grain.
Recipe — palindrome melodic phrase: note("<C4 Eb4 G4 Bb4>").palindrome() — goes up, then back down.
Recipe — jux variation (stereo trick): .jux(rev) — applies .rev() only to right channel; left stays forward. Wild stereo.
Envelope
| Method | Effect |
|---|
.attack(s) / .atk(s) | attack time (seconds) |
.decay(s) / .dec(s) | decay |
.sustain(0–1) / .sus(N) | sustain level |
.release(s) / .rel(s) | release tail |
.gain(N) | level |
.gate(N) | note duration multiplier |
Recipe — string swell (Kiasmos): .attack(2).sustain(0.5).release(3) — 2s ramp up, half-volume sustain, 3s tail.
Combining
The power is COMBINING these. A flat sawtooth becomes a string section with:
note("<C2 G1 Ab1 F1>").s("sawtooth")
.detune(0.1)
.attack(0.8).release(2)
.lpf(sine.range(400, 1200).slow(16))
.lpq(2)
.room(0.92).roomsize(8)
.delay(0.3).delaytime(0.5).delayfeedback(0.55)
.pan(sine.range(0.4, 0.6).slow(11))
.gain(0.4)
That's a stock sawtooth turned into a real string voice.
Diagnosing flatness
If a track sounds flat, ask in order:
- Is anything modulating over time? (sine.range on filter/gain/pan)
- Is the stereo image wide enough? (pan, jux)
- Are there delay tails that bridge events?
- Are there envelopes so notes don't just snap on/off?
- Are voices detuned so the chord isn't sterile?
- Is there any random variation (perlin, sometimes, degradeBy)?
