metronome-swarm

metronome-swarm winds up a metronome every time you touch a key.

A hundred metronomes wound up together and left to run down out of phase made Ligeti’s Poeme symphonique; this swarm is scaled to 16 and wound by your fingers. Each note-on winds an independent metronome on the played key: its tempo is a seeded uniform draw between bpm-lo and bpm-hi, its first strike sounds immediately at your velocity, and every later strike lands fade times softer than the last, never below 1. A metronome runs down after max strikes, or the moment your note-off for that key arrives, whichever comes first: your release stops that key’s metronomes. When a 17th metronome starts, it steals the slot of the oldest, which is already silent between strikes, so the steal makes no sound.

Note-ons and note-offs are consumed; only the swarm’s strikes reach the output, and everything else passes.

The swarm is a generator: it runs on its own seeded clock, the same seed and the same playing winding up the same swarm, and cleans up on a scene switch.

Parameters

Parameter	Type	Default	Range
seed	integer	required	any unsigned 64-bit value
bpm-lo	number	40.0	20..=400 bpm, at most bpm-hi
bpm-hi	number	208.0	20..=400 bpm
max	integer	24	1..=64 strikes per metronome
fade	number	0.97	0.5..=1.0 velocity factor per strike

Example

miditool.kdl

input "Roland"
output virtual="miditool Out"

metronome-swarm seed=17 bpm-lo=40 bpm-hi=208 max=24 fade=0.96
feldman-field seed=5 floor=6 ceiling=26 jitter=3

Tap a handful of keys and walk away: each one ticks at its own tempo, the whole room slowly running down, with feldman-field sinking everything toward a whisper. This is the poeme scene of examples/machines.kdl, where switch="kill" silences the swarm the moment you leave.

Try this

Narrow the tempo band and let the strikes live longer:

metronome-swarm seed=8 bpm-lo=112 bpm-hi=126 max=64 fade=0.99

Metronomes this close in tempo start almost together and drift apart audibly, the phasing patterns of process music emerging on their own. Hold the keys down only as long as you want each layer to survive; release is the off switch.