Although on the level of sound synthesis and structure there is hardly any relationship between my earlier, analogue Depths of Field pieces and Torso, there is one common aspect: all the sound material was organised into a family tree that shows how every material group is derived directly or indirectly from a source material by means of transformation processes. This family tree was subsequently interpreted as a ‘form potential’, and as such gave suggestions for the large-form construction of the piece.
Since in the Depths of Field pieces this source was an aleatoric structure, little had to be composed after all the material groups were produced; neighboring relationships were to a certain extent guaranteed by the source material’s structure and the transformation processes’ ‘transparency’ for this structure. The large form consequently emerged from the sound material by placing the transformations in a specific order.
In Torso, however, the source material consisted of a set of recorded violin sounds. A very sensitive contact microphone was placed at the bridge of the instrument, after which a rich variety of relatively abstract sound materials could be produced by just touching the body (its ‘torso’) in different ways. A continuous recording of approx. 15 minutes was later spliced into 19 segments, which again were sub-divided into a, b, c, …
The separate sounds were then all transformed one by one by means of various, mostly digital transformation processes, resulting in new material groups with an equal amount of separate sounds.
violin used for the sound material 
family tree for sound production 
score page from part 1 
score page from part 2
For the sound transformations I used the – nowadays obsolete – computer program Turbosynth. This program could recalculate samples in RAM on the basis of graphically patched modules with functions such as ring-modulation, filtering, enveloping, transposition, time stretching/compression, spectral inversion, etc.
Despite their complex micro structure, the resulting sounds show no musical development in themselves; every single sound or sound transformation represents a more or less static ‘field’. In order to create a large form that was musically meaningful, I felt that an additional structural principle had to be superimposed onto the material after all the sound transformations had been executed. For this purpose I used Gottfried Michael Koenig’s computer composition program Projekt 1.
With this program, the parameters of a musical structure are calculated on the basis of a number of processes that can vary from ‘very irregular’ (process 1), resulting in series without any repetition of list values, to very regular (process 7), allowing for large numbers of value repetitions. After all the input data has been entered (which includes addressing a separate process number to every parameter for each section), the computer calculates an output structure that can be read on the screen or printed in the form of a list.
The output of Projekt 1 was interpreted as follows:
| PR1 score file | Torso |
|---|---|
| entry point | entry point (multiplied x 10) |
| pitch | sound number (within a group) |
| register | material group number (within the family tree) |
| instrument number | sound layer (also indicating spatial position) |
In parts two and four, sounds with a clear pitch were transposed according to the pitch indication from the score file .
In the multi-track version of Torso, the instrument number also determined the spatial position of the sounds.
Torso was commissioned by the Fonds voor de Scheppende Toonkunst and was premiered at the Terza Prattika festival, Felix Meritis, Amsterdam.
year: 1998
duration: 26:30
tracks: 8
Available on the CD Kees Tazelaar: Electronic Compositions (CV NEAR 13)