talea

talea locks your notes to a repeating cycle of durations.

The talea is the rhythmic engine of the isorhythmic motet: Vitry and Machaut cycled a fixed row of durations beneath a repeating row of pitches, the two drifting out of phase. Messiaen revived the device in the Liturgie de cristal that opens the Quatuor pour la fin du temps, where duration cycles run under the music as if they had been running forever. Here the cycle is yours to write: each note-on takes the next duration from the list, wrapping around, and its note-off is scheduled then and there.

Your release is ignored: the cycle has already fixed when the note ends. Every note-on leaves with its note-off already scheduled, so note-ons and note-offs always balance and nothing can hang; retriggering a held key stacks another note with its own scheduled end.

Parameters

The durations are bare arguments, one to 32 of them. Plain numbers are milliseconds; with beats=true they are beat counts against the tempo (each still resolving to within 1ms and 60s); see Time and tempo.

Parameter	Type	Default	Range
durations	number arguments	required	1 to 32 entries, each 1ms..=60s
beats	boolean	false	true reads the entries as beats

Example

miditool.kdl

input "Roland"
output virtual="miditool Out"
tempo 90

talea 1 0.75 0.75 1 beats=true      // a 3.5-beat cycle

Three and a half beats per cycle: against a 4/4 count the row lands half a beat earlier on every pass, crossing the barline on its own schedule, the isorhythmic drift built in. Without beats=true the entries are milliseconds: talea 250 500 250 1000.

Try this

The Liturgie de cristal move: give each hand its own talea and let them drift out of phase.

tempo 90

fork {
    chain {
        key-range lo=0 hi=59
        talea 2 1 1 3 beats=true
    }
    chain {
        key-range lo=60 hi=127
        talea 1 1.5 0.5 beats=true
    }
}

A four-duration cycle below, a three-duration cycle above: even playing plain repeated chords, the two layers phrase themselves differently on every pass.