write-music

Imported from sdclibbery/limut (.claude/skills/write-music/SKILL.md). Install upstream with npx skills add sdclibbery/limut --skill write-music. Copyright stays with the author.

Write limut DSL code to produce music. Read the CLAUDE.md in the project root for full DSL reference. Below are practical patterns learned from examples.limut and the full index.html documentation.

Structure of a Piece

A piece typically has:

1. set bpm=N (common: 80-150)
2. set scale=NAME (minor, phrygian, dorian, mixolydian, lydian, penta, major, etc.)
3. Optional set root=N to transpose
4. Drum/percussion players
5. Bass player
6. Harmonic/pad players
7. Lead/melody players
8. Optional visuals (v lines)
9. Optional set ch=... for shared chord progressions

Each line defines one player: ID TYPE PATTERN, param=value, param=value

Limut is case insensitive; piano, Piano, and PIANO are all treated the same.

Basic Syntax

Comments

• // line comment
• /* ... */ block comment

Commands

• id synth pattern, params - define a player
• set id params - override player params
• set var=value - set global var
• preset name synth, params - create a synth preset
• include 'url' - include a limut source file

Multi-line commands

Commands can span multiple lines. A new command starts when the beginning of a line matches set , preset , or id type pattern.

Drum Patterns

Use play type with letter patterns. Each character is a 1-beat hit; . is rest.

Play Samples (full list)

Each letter maps to a sample folder. Multiple samples exist per letter (selected via sample=N).

Typical drum patterns

kd play X., room=0.1                           // four-on-floor kick
kd play (Xv)., room=0.1                        // kick with ghost note chord
kd play X..X.X.., room=0.1                     // syncopated kick
sd play ..O., room=0.1                         // backbeat snare
sd play ..(OH*)., room=0.2                     // snare with clap layer
hh play -, echo=1/4, amp=2                     // 8th note hats
hh play -[--]-[.-], fold, amp=2               // breakbeat-style hats
hh play .[::], echo=1/8                       // hat pattern with tight hats

Pattern Syntax

Brackets in patterns

• (...) = chord (play all simultaneously)
• [...] = subsequence (fit multiple events into one dur)
• <...> = supersequence (cycle through alternatives each pattern repeat)

Examples:

• X<...[.v]> = first time X then ..., second time X then .v
• [XX] = two kicks in one beat (double time)
• (OH) = snare and clap together

A chord in a pattern is written with NO separators — (047), not (0,4,7). Pattern notes are single characters juxtaposed, exactly as 0357 is four notes, so (047) is one chord of three. Commas belong to expressions, where a chord is (0,4,7) (see Chords under Expression Syntax) — so add=(0,4,7) is right and p1 lead (0,4,7) is a parse error: Invalid pattern: Missing bracket, expecting ). Same brackets, different separator rule, and the error message does not hint at it. For notes needing more than one character in a pattern, use the expression form via add= instead.

Pattern modifiers

• . = rest (silence)
• _ = continuation/tie (extends previous note, NOT rest)
• 0# = sharp
• 0b = flat
• 0= = extend duration by 50%
• 0! = shorten duration by 33%
• 0^ = 50% louder
• 0v = 33% quieter
• x^ = 50% louder (non-numeric, for play synth)
• 0a = other chars after digits become params; eg t tri 01g23, glide=this.g/2

Pattern literal

`01 23` = backtick pattern literal; whitespace is ignored, contents treated as literal

Pattern operators

• 01 loop 2 = play pattern only N times then stop
• 0123 crop 2 = crop pattern to N steps (repeats if needed)
• 1 + 2 = concatenate two patterns
• 1 * 2 = repeat pattern N times
• now 01 = play starting on next beat instead of from beat 0
• follow p1 = follow another player's pattern
• gamepad = generate notes from gamepad controller
• midi = generate notes from MIDI controller

Audio Synth Types

Basic oscillators

• play - sample player (letters/symbols for samples). Duration defaults to 1/2
• perc - sampled percussion. Duration defaults to 1/4, has choke group
• saw - sawtooth wave, oct=4
• sine - sine wave, oct=4
• square - square wave, oct=4
• tri - triangle wave, oct=4
• pulse - pulse wave, oct=3
• wave - waveform specified by wave param
• ping - sine wave ping, oct=5, simple envelope
• noise - white noise pad (AudioWorklet)

Detuned variants (thicker sound)

• dsaw - detuned sawtooth, oct=4
• dsine - detuned sine pad, oct=4
• dsquare - detuned square, oct=4
• dtri - detuned triangle, oct=4
• dbass - detuned sawtooth bass, oct=2
• dpulse - detuned pulse, oct=3
• dwave - detuned waveform specified by wave param
• swell - detuned triangle pad, oct=4

FM synthesis

• fm - FM base synth; configure operators with op1 to op6 params
  • op1={ratio:5.19,target:3,wave:'saw',depth:0.8,att:0.01,rel:0.1}
• fmbass - FM bass, oct=2
• bell - FM bell
• glock - FM glockenspiel, oct=4
• glass - FM glass/chime, oct=5
• xylo - FM xylophone, oct=4
• ethereal - FM pad, oct=5
• epiano - DX7-style electric piano

Complex synths

• audiosynth - base type; use play param for custom audio node graph
• piano - sampled piano
• pwm - pulse width modulation (AudioWorklet). pwm=1/2 for pulse width
• prophet - PWM with LFO pulse-width (AudioWorklet)
• supersaw - 7-oscillator supersaw lead, oct=4
• ambi - ambient drone, multiple sines
• multiwave - multiple oscillators: wave1={'saw',amp:[0:1]n,detune:wow}
• pitchedperc - synthesised percussion (click/hit/body/rattle components)
  • click={1}, hit={0,sample:'^',index:1,rate:3/2}
  • body={1,att:5ms,dec:400ms,freq:55hz,boost:150hz,wave:'sine',saturation:0}
  • rattle={1,att:0ms,dec:30ms,rate:1,filter:'lowpass',freq:55hz,boost:205hz,q:18}
• bd - preset kick drum based on pitchedperc. Params: accent, tone, tune=55
• io808 - TR-808 simulation. type='bd' selects sound. Params: level, tone, decay, snappy, tuning
• impulse - single pulse
• sample - pitched sample player. Use sample param for URL, start for playback offset
• external - microphone/line input. track=1, channel=1
• crackle - crackly sounds
• noisefloor - slowly varying noise floor
• bus - audio mix bus (plays continuously, all params per-frame). Implicit main bus exists

Special synths

• ! / stop / none - stop/remove a player

Melodic Patterns

Scale degrees (0-indexed): 0 = root, 1 = 2nd, 2 = 3rd, etc. Negative numbers go down.

// Melodic bass line
db dbass 0[.0][10]_, dur=1/2, lpf=[200:2000]s8, att=0, oct=(1,2)

// Arpeggio
arp dsaw 02435167, dur=1/2, sus=1/4, echo=3/4, lpf={[500:1500]l7,q:22}, att=0

// Chord stab
stab dsaw (0246), dur=[3,3,2]/4, att=0, sus=1/4, echo=3/4, lpf={[500:1700]l5,q:20}

// Pad
pad ethereal (024)(035), dur=4, room=0.7, oct=4

Value Syntax

Basic structure: value{modifiers}@interval

Numeric values

• 1 - constant number
• 0dB - decibel value (converted to gain; 0dB=1, +6dB2, -6dB0.5, -20dB~0.1)
• 100ms - milliseconds; 1s - seconds; 1Hz/1cps - Hertz; 1kHz = 1000Hz
• 1b - beats; 1cpb - cycles per beat; 1kcpb = 1000cpb; 1cpm - cycles per minute
• Missing value on param = 1 (eg monochrome same as monochrome=1)

Sequences and timevars

• [1,2] - sequence, one per event
• [] - equivalent to [0,1]
• [1,2]t3 - timed sequence, each value lasts 3 beats
• [1:12,2:4]t - timed sequence with variable timing per value
• [0:3]t1 - expanded timed sequence = [0,1,2,3]t1
• [1,2]l3 - linear interpolated sequence over 3 beats
• [1:12,2:4]l - linear interpolated with variable timing
• [1,2]s3 - smooth (S-curve) interpolated sequence over 3 beats
• [1,2]e - interpolated over event duration
• [1,2]e1 - interpolated starting at event start, 1 beat per value
• [0:!300ms,1:_[1/4b:1/2b]r,0]e - piecewise envelope with mixed timing
• [1:!200ms,0]e@s - segment-based (more accurate timing for envelopes)

Random and noise

• []r - random 0 to 1 each event
• [1,4,7]r - random choice from list
• [:9]r or [0:9]r - random float from range
• [0,1:7]r - weighted random (1 is 7x more likely than 0)
• [1,2]r4 - random, hold for 4 beats
• [1:3]r{seed:1,per:4} - deterministic seeded random
• []n - smooth Perlin noise 0 to 1
• [1:2]n4 - noise between 1-2, period ~4 beats
• []n{seed:1,per:4} - deterministic noise

Piecewise series

[v1:i1t1, v2:i2t2, ...]{p, repeat:0} - interpolate between values with custom control parameter

• Interpolation operators: :/ :\ linear, :_ const/step, :~ smooth bezier, :! exponential, :^4: power curve

Arithmetic

+, -, *, /, %, ^ (power), - (unary minus)

Chords

• (1,2,4) - play simultaneously. This comma form is for expressions (eg add=(0,4,7)); in a pattern the same chord is written without separators, (047) — see Brackets in patterns.
• | - concatenate chords: 1|2 = (1,2), (1,2)|(3,4) = (1,2,3,4)

Conditionals

• ?? - "if then": this.foo??5 returns 5 if foo is truthy, nothing if not (short circuits)
• ?: - "or else": this.foo?:5 returns foo if present, else 5 (short circuits)
• Ternary: this.foo>1 ?? 2 ?: 3

Comparisons

==, !=, <, >, <=, >=

Maps

• {x:0,y:1} - map with key-value pairs
• {2,y:1} - map with main value plus subparams (eg chop={2,wave:'tri'})
• Colours: {r:0,g:1,b:0,a:1} (RGBA), {h:1,s:1,v:1,a:1} (HSV), {labh:1,c:1,l:1} (LabLCH)
• Hex colours: #f00f (RGBA short), #ff0000ff (RGBA long), #f00 / #ff0000 (RGB, alpha=1)
• 'abc' - string value (single line; use \n for line breaks)

Lookups (dot operator)

• p1.amp - player param lookup (returns chord of all playing events)
• p1.amp.0 - chord index (wraps around)
• p1.pulse.max - chord aggregator: max, min, first, last, rand, count, sum, avg
• this.value - current event param
• this.freq - current note frequency
• {foo:2}.foo - map field lookup
• ([0,1]t1@f).accum - smoothly accumulate values

Modifiers

• {time:time*2+8} - modify the time expression
• {per:8} - repeat sequence every 8 beats
• {per:8,0:7,2:3} - force values at specific beat positions within repeat
• {step:1/2} - advance time in discrete steps
• Note: modifier and interval order can be swapped: []r@f{seed:1} = []r{seed:1}@f

Intervals

• @e - evaluate once per event
• @f - evaluate per frame (~60fps) for smooth animation
• Interval applies to nearest value: this.foo@e applies @e to foo only; use (this.foo)@e for the whole lookup

Variable lookup

• foo - lookup global var named foo; returns string 'foo' if no var exists
• foo{x:2} - call var as function with named params

Common Event Params

Timing

• dur=N - duration in beats (1/4=16th, 1/2=8th, 1=quarter, 2=half, 4=whole)
• dur=[3,3,2]/4 - common shuffle/swing pattern
• delay=N - event start time offset in beats
• delay={1/2,add:2} - delay with param overrides on delayed events
• stutter=N - split event into N evenly-spaced sub-events
• swing=N - swing amount (50=straight, 58-66=swung, 75=max dotted)
• swing={66,period:1/2} - swing with custom period (default 1/4)

Volume

• amp - player amplitude (defaults to event vel)
• vel - event velocity (default 3/4; controls amp and usually brightness)

READ ONLY params

• voice - voice index within a chord
• time - current time in beats this event has been playing
• idx - pattern index of this event
• exists - 1 if player is defined
• playing - 1 if player is currently sounding
• pulse - rise/fall value as note plays (pre-multiplied by vel)
• player - name of current player
• freq - note frequency in Hz (set by tonal synths)

Other

• rate - playback rate for samples, animation rate for visuals

Audio Params

Envelope

• att - attack time (default unit: beats). att=0 for sharp attack
• dec - decay time
• sus - sustain time. sus={level:0.5} for sustain level (default 0.8)
• rel - release time
• envelope - type: 'full' (ADSR), 'simple' (ADR), 'organ' (ASR), 'pad' (cosine crossfade), 'linpad' (linear crossfade), 'percussion' (R only). Or custom expression: envelope=[1:!300ms,0]e@s

Pitch & Tuning

• oct=N - octave (1=sub bass, 2=bass, 3=low, 4=mid, 5=high)
• oct=(2,3) - chord across octaves
• add=N - add scale degrees to pitch (per-event only)
• add={0,#:1} - sharpen; add={0,b:1} - flatten
• addc=N - add continuous semitones (per-frame, fractional). addc=wow for pitch drift
• detune=N - oscillator detuning in semitones
• vib=RATE - vibrato rate (default unit: cpb)
• vib={2,depth:1} - vibrato depth in semitones (default 0.4)
• vib={2,delay:1} - delay before vibrato starts (default 1/2 beat)
• glide=N - portamento time in beats. glide={1/3,curve:4} for curve shape (default curve:1)
• root=N - override root for this player only
• scale=NAME - override scale for this player

Filter

• lpf=FREQ - low pass filter. lpf={400,q:20} for resonance (default q:5). lpf={400,poles:4} for 24dB/oct
• hpf=FREQ - high pass filter. Same subparams as lpf
• bpf={FREQ,q:20} - band pass filter (default q:1). Multiple parallel: bpf1, bpf2 etc
• nf={FREQ,q:20} - notch filter (default q:1)
• apf1={FREQ,q:2} - allpass filter. Multiple apf1, apf2 etc (parallel, allowing phase cancellation)
• psf={f1:300,f2:2300,q:0.7} - phaser stage filter. Multiple psf1, psf2 etc (series)
• low=-6dB - low shelf EQ. low={-8db,freq:400} (default freq:200Hz)
• mid=-6dB - mid EQ. mid={-8db,freq:400,q:10} (default freq:600Hz, q:5)
• high=-6dB - high shelf EQ. high={-8db,freq:400} (default freq:1100Hz)
• Filter sweep: lpf={[200:2000]l8,q:15}

Effects

• room=N - freeverb (0.1-2). room={2,hpf:300,mix:1/4} (default mix:1/2)
• reverb=N - convolution reverb duration in beats. reverb={2,curve:3,hpf:300,mix:1/4} (default mix:1/2, curve:5)
• echo=TIME - echo delay. echo={1,feedback:0.8} (default feedback:0.35). Bus echo: echo={1,max:2}
• chorus=N - stereo chorus. chorus={1,mix:1/4}
• phaser=RATE - phaser (default unit: cpb). phaser={1/3,mix:1/4}
• flanger=RATE - flanger (default unit: cpb). flanger={1/3,mix:1/4}
• chop=N - tremolo/gating (default unit: cpb). chop={2,wave:'triangle',mix:1/4} (waves: sine, square, triangle, saw)
• ring=FREQ - ring modulation (default unit: Hz). ring={32,wave:'saw',mix:1/4} (default wave: triangle)
• drive=N - overdrive/soft clip (1/32=gentle, 1/4=distortion, 1=fuzz). drive={1,gain:2,mix:1/4}
• fold=N - wavefolder. fold={1,gain:2,mix:1/4}
• clip=N - hard clipping. clip={1,gain:2,mix:1/4}
• noisify=N - distort into noise. noisify={1,gain:2,mix:1/4}
• bits=N - bitcrusher (1=very distorted, 32=clean, 0=off). bits={4,gain:2,mix:1/4}
• suck=N - scale down small amplitudes (gated tail effect). suck={1,gain:2,mix:1/4}
• compress=RATIO - compression. compress={12,gain:2,threshold:-40dB,knee:10dB,att:0.1,rel:0.2}

Spatial

• pan=N - stereo position (-1 to 1)
• pan=(-1,1) - hard pan left and right
• mono - force signal to mono

Other audio params

• choke=GROUP - choke group (string); notes cut off others in same group across players
• sample=N - with play: choose sample set. With sample synth: URL of audio file
• sample={32,pitch:261.6} - specify original sample pitch (default 261.6Hz = C4)
• start=N - sample playback start time (default unit: seconds)
• wave=NAME - waveform: sine, square, sawtooth/saw, triangle/tri, pulse, plus many more: ah, bass, brass, buzzy, celeste, ethnic, organ, piano, trombone, wurlitzer, etc. (hyphenated names need quotes)
• bus=ID - mix to specified bus player (default: main)
• cutoff - filter cutoff 0-1 (for presets that support it)
• resonance - filter resonance (for presets that support it)

Visual Synths

• blank - solid colour
• clouds - moving clouds
• kal - kaleidoscope
• swirl - psychedelic swirl
• julia - Julia set fractal
• lines - twisting lines
• blob - morphing 3D blob
• streetlight - passing streetlights
• grid - square grid
• glow - additive glow
• stars - exploding stars
• bits - bitwise fractal patterns
• xor - bitwise xor patterns
• gradient - simple y gradient
• shadertoy - shadertoy shader (use id param; must be public+api)
• image - online image (use url param; must support CORS)
• webcam - webcam feed. device param for device index/label. width/height for resolution
• text - text display. text={'Hello',font:'times',size:'144',linesize:0.7,y:1/4,x:2/3,style:'bold italic'}
• buffer - render target. Other synths render into it with buffer=ID
• scope - audio waveform display
• scopefft - frequency spectrum display
• readout - digital value display
• dmx - DMX lighting output. channel, set, lights, addl, mul, min, max params

Visual Params

• add - add to pattern value
• zorder - draw order (default: line number / 1000)
• fade - brightness fadeout
• time - override shader time (default unit: beats; overrides rate and sway)
• rate - shader time progression rate
• pulse - audio signal effect on visual value
• sway - audio signal effect on visual time
• loc - position/size: {x:0,y:0,w:2,h:2} for fullscreen. Coords: (-1,-1) bottom-left to (1,1) top-right
• window - display only portion matching screen position
• scroll - scroll shader: {x:0,y:0}
• repeat - repeat shader section. repeat={1/2,x:0.1,y:-0.05}
• zoom - zoom: {x:1,y:1}
• rotate - rotation in full turns (1/2 = 180 degrees)
• mirror=N - number of mirror planes. mirror={10,rotate:1/4,fan:1}
• fore - foreground colour
• mid - middleground colour (defaults to midway between fore and back)
• back - background colour
• pixellate=N - pixellate to N pixels in x. pixellate={10,y:20}
• perspective=N - perspective warp (negative to invert). perspective={-1,shade:1/2}
• tunnel - tunnel/slitscan warp
• ripple - ripple distortion. ripple={1,scale:1/4}
• additive - additive blend
• blend - blend mode: additive, subtractive, average, multiply, invert, min, max
• monochrome - 0=normal, 1=monochrome
• vignette - edge fadeout. vignette={1/2,aspect:4/3,cutoff:0.95}
• vhs - VHS tape effect
• recol - recolour: oil, hue, fire, sunset, neon, titanium
• contrast - power contrast curve (0=none)
• buffer=ID - render to a buffer synth
• rez=N - buffer render target resolution scale (default 1/2)
• feedback - buffer video feedback. feedback={zoom:1.01,ripple:1/32,contrast:0.005}

Main Vars (set, not readable)

• bpm - beats per minute (resets unless set every update)
• scale - scale name (resets unless set every update)
• root - root pitch offset in semitones (fractional OK for tuning nudges)
• beat.readouts - beat counter display: beat.readouts=(3,12) (default: (12,16,32), max 3)

Predefined Vars

• time - current time in beats
• wow - smooth random pitch drift for analog feel; eg addc=wow
• tg - trance gate signal (flips on/off every quarter beat)
• drop6_2 through drop63_1 - predefined on/off drop patterns (eg [1,0]t[6,2])
• tile_full, tile_tl/tr/bl/br/m, tile_h1-h5, tile_v1-v5 - visual locations
• fullscreen - full screen tile
• tile_random/tile_rand - random location tile
• sparkle - small random location tile
• droplet - small tile falling down screen
• spark - small tile flying outwards
• gravity - accelerating downward motion (combine: spark+gravity)
• firefly - random insect-like motion
• Colours: transparent, black, darkgray, gray, lightgray, white, red, orange, yellow, green, blue, indigo, violet, neonpink, neongreen
• random - random colour
• rainbow - colour cycling through rainbow

Functions

• abs{-1} - absolute value
• sign{-1} / sgn - sign (-1, 0, 1)
• pitch{1} - frequency for scale degree. pitch{4#} sharp. pitch{0,oct:3,scale:minor,root:2}
• eventpitch{} - frequency based on current event params
• floor{1.5} / ceil{1.2} / round{1.7} - rounding. floor{1.7,to:1/2} rounds to precision
• accum{1} - accumulate value over time (only rises)
• smooth{[]r@f} - smooth a value. smooth{x,att:4,dec:4} or smooth{x,2} combined rate
• rate{[0:1]l1@f} - rate of change in units per beat
• first{3,1,2} / last{3,1,2} - first/last argument
• min{3,1,2} / max{3,1,2} - min/max of arguments
• count{3,1,2} / sum{3,1,2} / avg{3,1,2} - count/sum/average
• rand{3,1,2} - random choice from arguments
• rand - pseudo-random 0-1 (time-hashed; respects step/per modifiers)
• euclid{3,from:8} - Euclidean rhythm generator. euclid{3,from:8,offset:1} for rotation
• sin{x} / cos{x} / tan{x} - trig functions (radians)
• time - current time in beats (respects modifiers)

Node Functions

For building custom audio graphs with >> connect operator and audiosynth:

• osc{'sawtooth',freq:440,phase:0} - oscillator node
• const{1} - constant value node
• gain{1} - gain node
• delay{1/4b,feedback:...,max:1b} - delay node
• panner{0} - stereo panner (-1 to 1)
• sample{sample:'url',start:0s,rate:1} - sample player. Also: sample{sample:{x}->...,length:0.2s} function-generated
• sample{sample:'url',loopstart:1,looplen:2} - looping sample
• biquad{'lowpass',freq:440Hz,q:5} - biquad filter (lowpass/highpass/bandpass/notch/lowshelf/highshelf/peaking)
• compress{ratio:0,threshold:1/316,knee:100,attack:0.01s,release:0.25s} - compressor
• convolver{env:{x}->...,length:1s} - convolver reverb. Stereo: convolver{env:{l:{x}->...,r:{x}->...},length:1s}
• shaper{{x}->...,samples:2,oversample:'2x'} - wave shaper ('2x', '4x', 'none')
• series{...,count:2} - repeat chain in series
• loop{...,feedback:...} - audio feedback loop (must contain delay)
• mix{...,mix:1/2} - dry/wet mix. Also mix3 through mix8 for fixed ratios
• stereo{l:...,r:...} - split/process/join stereo channels
• flipper - swap L/R channels
• idnode / dry / thru - pass-through node

Nodes Library (include 'lib/nodes.limut')

Helper functions wrapping node functions (all args can be positional):

• lpf{freq,q:5} / hpf{freq,q:5} / bpf{freq,q:5} / nf{freq,q:5} / apf{freq,q:5} - filters
• lpf4{freq,q:5} - 4-pole low pass
• lsf{gain,freq:1100Hz} / hsf{gain,freq:1100Hz} / pkf{gain,freq:1100Hz} - shelf/peak EQ
• lfo{freq,wave:'triangle',lo:0,hi:1,phase:0} - LFO (any frequency)
• osc.sin{freq} / osc.saw{freq} / osc.square{freq} / osc.tri{freq} / osc.pulse{freq} - typed oscillators
• drive{amount:1/2} - overdrive waveshaper
• stanh{gain:3/2} - tanh saturation (alias for shaper.tanh)
• shaper.tanh{gain} / shaper.atan{gain} / shaper.poly{gain} / shaper.pow{curve} / shaper.asym{gain,bias} / shaper.diode{gain,pos,neg} - waveshapers
• compressor{...} / limiter{...} - dynamics

Don't put a filter in a modulator chain

A filter feeding an audio path is free. A filter in a chain that ends at a param is not: superosc{freq: eventpitch*(1+(noise>>lpf{1000})/3)} builds a biquad per note inside a param subgraph, and Chromium leaves cost resident on the audio thread for every one of them, so a fast line slowly eats the audio thread until it drops out. Nothing in the DSL fixes it.

Smooth a modulator with a slow source instead of a filter: noise{rate:1/20} is white noise band-limited to ~1.1kHz (rate scales the band: 1/50 -> ~440Hz), with no filter in the chain. It is louder than the lowpassed version — roughly 2.4x for lpf{1000} at the default q:5 — so scale the depth down to match. keytar in preset/synth.limut is the worked example.

Effects Library (include 'lib/effects.limut')

Wet-path effects (wrap in mix{} for dry signal):

• echo{time:1/8b,feedback:0.7,max} - echo with feedback and dry path
• pingpong{time:1/4b,feedback:0.7} - stereo ping-pong delay
• reverb{length:1b,curve:3} - convolution reverb
• flanger{control:[0,1]l8@f,feedback:0,lo:0.0005,hi:0.007} - flanger
• phaser{control:[0,1]l4@f,lo:300Hz,hi:2600Hz,stages:4,q:1/2} - phaser
• shifter{ratio,length:0.03} - pitch shifter
• shimmer{ratio:2,length:2s} - shimmer reverb
• tape{wow:1,cut:-10db} - cassette tape effect
• airverb{delay:1/2b} - airy reverb with flanger and stereo pingpong
• grain{ratio,length:0.03,phase:0} - granular resynthesis grain
• demon{} - demon voice effect (for vocals/mic)
• ultracomb{f:...,p:...,s:...,stages:6} - ultracomb filter (growling sounds)

User Input Functions

• slider{0.1} - on-screen slider. slider{name:'Foo',min:-5,max:5,curve:2}
• gamepad{1} - gamepad axis (-1 to 1). gamepad{button:0} (0-1). gamepad{'lsh'} left stick horizontal. gp is alias
• midi{70} - MIDI control/note (0-1). midi{36,9,1} (control 36, channel 9, port 1)
• midi{'bend'} - pitch bend (-1 to 1). midi{'notes'} - chord of playing notes. midi{'vel'} - velocity

Console Commands

• list - list all player base types including presets
• list audio - list filtered by string

Preset Libraries

Synthwave (include 'preset/synthwave.limut')

Audio: moroder, blade, laserharp, synlead, synpluck, synbass, chiparp, softpad, space, blues, basspluck, bloom, pick, softkeys, epiano, lushpad, stringpad, oxy, vambi, cybass, cydist, cyborg, hiss, blips, chime, play80s Visual: neongrid, neonbars, neonbits, neonlines, neonsine, neonheart, neonshapes, skybars, sun, sunsetsky, vhsbuffer Many support cutoff param (0-1, default 1/2). Some support decay param.

808 (include 'preset/808.limut')

Individual: bd808, sd808, oh808, ch808, cb808, cp808, ma808, ht808, mt808, lt808, hc808, mc808, lc808, cl808, rs808, cy808 Combined: tr808 (all-in-one; pattern chars select sound: x/v=bd, o/i/u=sd, h/*=cp, -/:/a=ch, ==oh, ~=cy, k=cl, m=mt, t=rs, s=ma, p=mc, e=cb; ^ flag for accent), h808 (hihats; o flag for open), t808 (toms; h/l flags), c808 (congas; h/l flags)

909 (include 'preset/909.limut')

Synthesized: bd909 (level, tune, attack, decay), sd909 (level, tune, tone, snappy), h909 (level, chdecay, ohdecay; o flag for open), cp909 (level), cc909 (level, tune), rc909 (level, tune), t909 (level, tune, decay; l/h flags), rs909 (level) Sampled (lighter CPU): bds909, sds909, hs909, cps909, ccs909, rcs909, ts909, rss909 All: event value gives accent.

TB-303 (include 'preset/303.limut')

tb303 - acid bass. Controls: wave ('saw'/'square'), cutoff, resonance, envmod, decay, accent (all 0-1, default 1/2). Pattern flags: a accent, u up octave, d down octave, s slide. Example: b tb303 `0a2u2b0d 0u0a2d3 00u0a0d 0da4ua5a6u`, cutoff=[1/4:1]n3, resonance=0.8, accent=1

Trance (include 'preset/trance.limut')

trance - classic supersaw lead (default add=(0,2)). Controls: cutoff, decay, detune (all 0-1).

Techno (include 'preset/techno.limut')

Includes 909, 303, trance libraries. Audio: hollow, tinbass (cutoff), sweep (cutoff), robot, techbass (cutoff, decay), growl

House (include 'preset/house.limut')

Includes 909, 303, trance libraries. Audio: m1organ (cutoff), reese (cutoff, detune), donk (cutoff, decay), didgeridoo

Available Scales

chromatic, major, minor, pentatonic/penta, minorpentatonic/minorpenta, mixolydian, dorian, phrygian, lydian, locrian, harmonicminor, harmonicmajor, melodicminor, melodicmajor, diminished, egyptian, blues, wholetone, chinese, hungarianminor, romanianminor, halfwhole, wholehalf, bebopmaj, bebopdorian, bebopdom, bebopmelmin, majorpentatonic, aeolian, dorian2, yu, zhi, prometheus, indian, locrianmajor, lydianminor, minmaj, susb9, lydianaug, lydiandom, melmin5th, halfdim, altered

Set for Groups

set (p1,p2,p3) room=0.7, echo=3/4    // apply params to multiple players
set p* amp=0                           // wildcard: all players starting with p
set !p* add+=7                         // all players NOT starting with p
set * swing=58                         // all players
set ch=[0,2,4,3]t8                     // define shared variable

Operator overrides

• add+=N - add to existing value
• amp*=N - multiply existing value
• oct+=N - shift octave

Bus Mixing

There is an implicit main bus. Players can route to named buses:

fx bus 0, echo=1/2, room=0.5
bass dbass 0, bus=fx

Override main bus: set main echo=1/2

Genre Recipes

Techno (120-140 bpm, minor/phrygian)

set bpm=130
set scale=phrygian
kd play X., room=0.1
hh play -, echo=1/4, amp=2
sd play ..(H*)., room=0.2
db dbass 0, dur=1/4, lpf={[150:800]r,q:12}, att=0, amp=2
pad dsaw (0246), dur=8, envelope=pad, lpf=[500:3000]l16@f, oct=(3,4), amp=1/2

House (120-128 bpm, minor/dorian)

set bpm=125
set scale=minor
kd play X., room=0.1
hh play .[::], echo=1/4
sd play ..O., room=0.3
bass fmbass 0[.0][.0][0.], dur=1/2, sus=1/2, lpf={[300:800]n4,q:8}, oct=(2,3), att=0, amp=0.8
pad prophet (0246), dur=8, oct=(2,3), amp=1/2, room=0.7

Ambient (60-90 bpm, major/lydian/penta)

set bpm=70
set scale=penta
pad ethereal (024)(035), dur=4, room=2, oct=(3,4), amp=1/3, pan=[-1:1]r
pi piano 0, dur=[2,4], add=[-2:3]n1/4, amp=[0:1]n6, room=0.7, oct=5
n noise 0, dur=8, amp=1/16, lpf=[800:1200]n4, pan=(-1,1), room=2

DnB (160-180 bpm, minor)

set bpm=170
set scale=minor
kd play X..X.X.., room=0.1
sd play ..O., room=0.1
hh play -[--]-[.-], amp=2, echo=1/4
db dbass 0, dur=1/4, lpf=[200:1000]l8, att=0, oct=(1,2), amp=2

Acid (125-135 bpm, phrygian)

set bpm=127
set scale=phrygian
kd play X., room=0.1
hh play -, amp=2
b saw 00[43]-707[-32]-4, dur=1/2, oct=2, amp=2, echo=3/4, lpf={this.freq*[2:50]n4,q:25}

Synthwave (80-120 bpm, minor/phrygian)

set bpm=100
set scale=minor
kd play X.v., room=0.2
sd play ..O., room=0.2
hh play -===---=, dur=1/4, amp=2
db dbass 0, dur=1/4, lpf={[200:1400]n8,q:15}, amp=1+wow, room=0.2
pad blade (024)(035), dur=4, oct=3, add=[0,4,5,6]t8
arp synpluck 02479742, dur=1/4, echo=3/4, lpf=[500:3000]l11

Breakbeat/IDM (120-140 bpm, minor/phrygian)

set bpm=132
set * swing=58
kd play V., room=0.1
hh play [.-]-[.-][--], fold, amp=2
sd play ..*., fold, room=0.1
b saw .0, dur=1/2, oct=2, lpf={[200:1500]l8,q:12}, flanger=1/7, amp=3/2

Tips for Good Music

1. Layer sparingly: 4-8 players is plenty. Too many = mud.
2. Use filter sweeps: lpf={[300:2000]l8,q:15} adds movement and interest.
3. Echo/delay: echo=3/4 (dotted quarter) or echo=1/2 creates rhythmic interest.
4. Shared chord progressions: Define set ch=[0,2,4,3]t8 and use add=ch on multiple players.
5. Pan for width: Spread elements with pan=(-1,1) or pan=[-1/2:1/2]r.
6. Room/reverb: Use sparingly on drums (0.1-0.3), more on pads/leads (0.5-2).
7. Sidechain-like pumping: amp=1-kd.pulse.min makes things duck with the kick.
8. Build/drop structure: Use set overrides and commented lines for live arrangement.
9. Octave layering: oct=(2,3) or oct=(3,4,5) for thickness.
10. wow for organic movement: addc=wow adds subtle pitch drift to pads/leads.
11. Swing: set * swing=58 gives a nice groove (50=straight, 66=heavy triplet swing).
12. Amp variation: amp=[0:1]n4 for perlin noise dynamics, amp=[]r for random.
13. Chop/gate: chop=2 or chop=4 for rhythmic gating on pads.
14. Follow: dsf dsquare follow ds - layer the same pattern with a different synth.

Production Idioms (from real pieces)

Mastering chain on main bus

Almost every finished piece ends with one of these on set main:

set main compress={2,gain:2}, drive=1/32                     // gentle glue + warmth
set main compress={2,gain:2}, drive=1/64, reverb={1,mix:1/4} // + tail
set main compress={3/2,gain:3/2}, drive=1/96, amp=3/2        // heavy techno glue

drive 1/96 → 1/16 trades subtle warmth for audible saturation. compress ratio 2-3 with gain:2-3 is the sweet spot.

Multi-bus organization (techno/house template)

Separate buses per stem so each can be shaped independently:

set p* bus='bp'                                 // all perc → bp
set !p* bus='blead'                              // everything else → blead
bp bus 0, compress={2,gain:2}, drive=1/32, amp=2/3
blead bus 0, compress={2,gain:2}, reverb={2,mix:1/3}, amp=1/2

Common bus names: bp/bperc, bb/bbass, blead/bl, be (external).

Sparse delay idiom (delay|=[...]t[N,M])

Adds occasional delay throws without changing every event:

set p* delay|=[(),[1,3]r/4]t[14,2]    // 14 bars dry, 2 bars random throws
set p* delay|=[(),[1,3,5]r/4]t[13,3]
delay=[0,(0,[1/4,3/4]r)]t[7,1]        // single-player form

|= (concat-assign) appends to existing delay rather than overwriting.

Pattern variation with crop and +

b reese 0_7 crop 14 + 89             // 14 beats of 0_7, then 89
ps sd909 ..0 crop 16
t trance 72. crop 14 + 89

Sidechain-style ducking via pulse

amp=2/3+kd.pulse.0/3                       // pad swells with kick
contrast=3-2*bs.pulse.max                   // visual reacts to bass
zoom=1+smooth{main.pulse,att:1/2,dec:1/2}   // smoothed pulse for visuals

Visual + buffer feedback (canonical setup)

vk kal 1, buffer='vb', blend=max, contrast=3, fore=neonpink
vb buffer 0, feedback={fore:0.95,zoom:1.01,rotate:0.001}

Common feedback knobs: fore:0.85-0.97 (decay), zoom:1.001-1.05, rotate, ripple, scroll, mirror. Reactive: feedback={fore:0.85+0.15*pk.pulse.0,zoom:1.02}.

Webcam + recolor

vw webcam 0, vignette=0, buffer='vb', recol=neon, blend=max
vb buffer 0, loc=tile_tr, feedback={fore:0.9,zoom:1.02}

VHS retro look

v kal 0, vhs, vignette={1/2,aspect:4/3}, contrast
vb vhsbuffer 0, feedback={fore:0.85}

Build/drop arrangement via riser

riser is typically a slider ramp. Pieces stash a "drop" block as comments:

// set (b*,p*) hpf=10000-10000*riser^3    // sweep filters open
// set t cutoff=riser^3                    // open lead filter
// f sd909 2, level=riser^6                 // snare roll fades in

Define with set riser=slider{0,name:'Riser'}.

Euclidean rhythms

ph h909 0, o=euclid{16,from:[19,23]t4}-1     // open-hat pattern
b tb303 0, amp=euclid{32,from:53}-7/8         // sparse 303 line
o m1organ 0, dur=euclid{7,from:16}/4          // polymeter via dur

One-shots with now ... loop 1

boom play now [(vx)(vX)(VXM)] loop 1, room=2, echo=0.46
whoosh dsaw now (047) loop 1, envelope=simple, att=1/2, rel=3

now starts on next beat (not beat 0); loop 1 plays once.

Layered delay copies via subparams

Layer a delayed copy with different params on the same event:

delay=(0,{1/4,oct:3})                     // dry + delayed-up-an-octave
delay=(0,{3/4,oct:2,addc:19})             // detuned/octave-shifted
delay=(0,{1/2,add:1,stutter:2})           // multiple overrides

Shared chord progressions via set ch=...

set ch=[(0,2,4,7),(0,3,5,7),(1,3,5b,7),(1,3,4,6#)]t4
p dsaw 0, add=ch, glide=2/3
l sine 0, add=ch.rand, oct=5      // .rand picks a voice
b bass 0, add=ch.0                 // .0 picks first voice

Non-percussion targeting with set !p*

set !p* add+=[2,-1,1,0]t4
set !p* bus='blead'

Drum preset notes

• 909 synth (bd909, sd909, h909, cp909, t909, rs909, cc909, rc909): pass attack flag to bd909 for pitch-envelope click. Params: level, tune, decay, tone, snappy.
• 909 sampled (bds909, sds909, hs909, cps909, ts909, rss909, ccs909, rcs909): much lighter CPU — prefer for dense patterns.
• h909/hs909: pattern char o = open hat. Drum char letters in patterns also pick variations.
• tb303 flags: a=accent, u=up oct, d=down oct, s=slide.

Live-coding scaffold

Typical improv file:

include 'preset/synthwave.limut'        // or techno/house
set scale=minor
set bpm=120
set main compress={2,gain:2}, drive=1/64

vk kal 0, buffer='vb', blend=max, contrast
vb buffer 0, feedback={fore:0.95,zoom:1.01}

pk bd909 0..., attack
ph h909 ..0, swing=54
ps sd909 ..0., swing=58

b tb303 0, cutoff=[0:1]n4, resonance=7/8

// l trance 0_7, decay=5, reverb=2          // bring in lead
// pad softpad (024), dur=4
// set (p*,b) amp=0                         // drop block
// set t cutoff=riser^3