`fx(...)` --- Shared Effects

fx() makes a bus: one reverb, one delay, one filter that several sounds go through together — three voices in one room rather than three rooms. Any sound can be sent to it: synths, audio files, speech.

Syntax

fx(room, reverb:{mix:0.5, time:4}) a bus called room, with a reverb fx(room, [a1, a2, a3]) these sounds go through it fx(room, a1, a2, delay:{time:0.375, fb:0.4, mix:0.2}) synth(uid:pad, wave:saw, freq:110, bus:room) ... or a sound says so itself audio(uid:rain, src:rain, bus:room) fx(room, reverb:{mix:follow(beat.phase, 0.2, 0.8)}) fx(room, filter:{type:lp, freq:follow(bass.low, 300, 6000)}, amp:0.8) level(room, 0, 8) the whole bus faded over 8 beats synth(uid:pad, bus:none) pad its own way again fx(room, reverb:{mix:0.4}) run again without its delay: the delay comes out fx(room, delay:off) ... or one taken out by name fx(room, off) the bus gone; its sounds go their own way

Parameters

param	description
(first name)	The bus: any name. Made the first time it is named — by `fx()` or by a sound's `bus:` — with no effects until they are given.
(more names, or a list)	Sounds to send through it, by their uid.
`reverb`	`{mix, time, damp, pre}` — the same room as a synth's reverb. `mix` can `follow()`.
`delay`	`{time, fb, mix, tone, sat}` — an echo; `fb` up to 1.5, past 1 running away into a held squeal (feedback). `mix` and `fb` can `follow()`.
`filter`	`{type, freq, q}` — type `lp`, `hp`, `bp` or `notch`; `freq` and `q` can `follow()`.
`sub`	An octave pedal's sub, as a synth's `sub:` -- `{level, octave, tone}`. First in the bus.
`drive`	A soft clip, 0..1, as a synth's `drive:`. After the sub.
`fuzz`	A fuzz pedal, as a synth's `fuzz:` -- `{starve, gain, bias, tone}`, and `level` (0.25): how loud it comes out (a fuzz comes out as loud whatever goes in). After the drive, before the filter.
`fold`, `clip`, `ring`, `comb`, `crush`	As a synth's grit: a wavefolder, hard clipping, ring modulation, a comb fed back, a bitcrusher. After the fuzz; each value can `follow()`.
`amp`	The bus's own gain (1, at most 2). Can `follow()`.
`delay:off`	Takes that effect out (`reverb:off`, `filter:off` too).
`off`	`fx(room, off)` takes the bus away.

On a sound — synth(), audio(), say() — bus:room sends it through room, and bus:none takes it out again.

How it works

Sending is by name. Every voice of a sound goes through the bus: the ones sounding now, and those still to come — each new note of a synth, each voice a poly: synth adds.
A sound's own effects stay its own. A synth with its own reverb: goes through that first, then into the bus with the others.
Changing the bus keeps it playing. Run fx(room, …) again: a new mix or filter glides there; a new room crossfades while the old one rings out what it heard; adding or taking away a delay or filter rewires it with the old tails left to die away.
The line is the bus's effects. An fx() line naming effects puts on those and takes off any it no longer names: take the delay:{…} out of the line, run it again, and the echoes stop (those already sounding die away). A line that only sends sounds (fx(room, [a1, a2])) or only nudges (fx(room, delay:{mix:*0.5}), all relative) leaves the rest as it is.
One pedal for everything sent. sub:, drive: and fuzz: on a bus are one pedal for every sound and voice in it, in that order, then the filter, delay and reverb. It is cheaper than a fuzz on each voice (four voices: under half the cost), and it is another sound: the bus hears the notes after their envelopes, so the fuzz squashes them (long sustains, as a pedal does), and it hears them together, so a chord's notes grind against each other. The sub follows the strongest pitch.
The bus is a name too: level(room, 0.5) turns it down, level(room, 0, 8) fades every sound in it together.
Times are beats, as everywhere: reverb time and pre, delay time.

Example — one fuzz for a whole bass

fx(dirt, sub:{level:1.2}, fuzz:{starve:0.2, gain:40, tone:6000}, filter:{type:lp, freq:2200}, reverb:{mix:0.3}) synth(uid:s1, wave:square, degree:Prand(0, 2, 3, 5, inf), stack:[0, 7], poly:4, root:A2, dur:1.5, bus:dirt)

Example — three sounds in one room

fx(room, reverb:{mix:0.5, time:4, damp:2500}) synth(uid:a1, wave:sine, freq:Prand(220, 330, 440, inf), dur:2, amp:0.06, pan:-0.7, bus:room) synth(uid:a2, wave:triangle, freq:Prand(165, 247, inf), dur:3, amp:0.05, pan:0.7, bus:room) synth(uid:a3, wave:saw, freq:55, amp:0.04, filter:{type:lp, freq:600}, bus:room) fx(room, reverb:{mix:0.9, time:8}) later: the room opens out under all three