“Schaakul” is the phonetic spelling of the Dutch word for “chain” (schakel). In my composition, chain reactions are shown between
– a so-called “”mother tape” (project “the tape”) created by the group “Neue Musik” Berlin;
– a version processed with a tempophone; and
– a composition for two synthesizers, which are controlled live by a portable computer;

The listening score of the “Berlin-tape” was re-analyzed (microstructures) and ordered according to the density of time, pitch, material and volume (macro structures). These form the starting point for the assignment of the computer composition adapted to the “Berlin-tape”.

The computer composition consists of seven parts.
1) Rhythmic patterns, constructed and adapted from exponential curves;
2) glissandi, which correspond to a sinus function in terms of pause scansion, volume and vibrato;
3) sound formations, which are proportional to the density of time and notated in straight lines;
4) random programme with predefined sound material and time grid;
5) improvisation with a live programme and synthesiser;
6) within the ostinato, an attempt is made to synthesise 1, 2 and 3, i.e. rhythmic patterns, glissandi and sound formations;
7) final section.

In parts 4 and 6, the performer tries to support the intended tensions live on the synthesizer. To do this, he recalls sections of the simple musical motif that was previously entered into a sequencer. (The sequencer stores volume and pitch via electronic voltages that can be called up via the synthesizer).
The sound material results from pitch measurements on five East African plucked instruments, so-called ‘klimps’.

‘Schaakul’ is to be understood as an experiment in combining “exotic” sounds with complicated, non-square-related (i.e. in the ratio of natural numbers) rhythms. This connection is made by means of a computer, which was able to break up historically practised musical ideas and thus function as an intermediary between composer and material. Therefore, there is no question of a restriction of compositional freedom through working with the computer.

“The duration of “Schaakul” (21’06) was originally the same as the composition “Chaines”. Only the title was different. This resulted in the later tape version “Chaines”, which was shortened to 9’38”.