Program Note

…until… (1972)
Version 10 for Double Bass (2015)
Version 7 for Guitar (1981)

Every version of …until… is based on the following set of instructions,
formulated in 1972:

Play a succession of pitches, the frequency ratios of which
measured against a continuous drone can be expressed as pairs
of contiguous whole numbers; a unison with the drone is also
possible.
Repeat this succession continually, at first without any change in
it; after a while replace the pitch with the largest frequency ratio
numbers at its position in the succession by another pitch with
ratio numbers not necessarily contiguous and at least equal in
size if not larger. Do this at first sporadically, then increasingly
often, until it is the rule. Repeat this process with all the other
pitches in order of decreasing ratio numbers. After all pitches have
been replaced, the new succession ought to be a phase-shifted
transposition of the original by an interval that is smaller than any
of those between the initial pitches and the drone.
Continue repeating the succession, gradually shifting the drone,
slowly and continuously, by the same interval; during further
repetitions start dropping the pitches one by one, again starting
with the pitches with the highest ratio numbers against the present
drone – hold the last remaining pitch for a while.

The rhythmic scheme of …until… has varied from version to version.