"Depths of Field" is a series of compositions that are based on experiments in which not just separate sounds, but even complete sound structures are generated by means of voltage-control techniques in the analog studio of the Institute of Sonology.
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| voltage controlled studio of the Institute of Sonology |
By doing so, these compositions try to connect to the series of electronic compositions "Funktionen" from the late sixties by Gottfried Michael Koenig.
The title "Depths of Field" refers to a theoretical text by Koenig, in which he proposes the term "Field Composition" for a compositional strategy in which the techniques of "System Composition" (serial) and "Chance Composition" (aleatorics) are integrated to a large extend.
Each "Depths of Field" piece is based on its own initial sound material, that directly or indirectly forms the basis for further transformation-processes. The results from these processes are organized into a family-tree, that is interpreted as a 'form potential', and as such gave suggestions for the large-form constructions.
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| family tree for Depths of Field no.3 |
For most production- and transformation-processes, the parameter-values are selected from random curves that were derived from the amplitude of slowed down noise-sources and stored on tape as control-signals.
For the realisation of these pieces much is owed to Sonology's former head of the electronics department Jo Scherpenisse, who designed, build and maintained much of the essential equipment.
Depths of Field no. 1 to 4 were commissioned by the Fonds voor de Scheppende Toonkunst.
click to play an excerpt of Depths of Field no.1
The studio work for D.O.F. no. 1 started with the production of a 4-track tape with a duration of 8 1/2 minutes, on which the individual tracks are statistically equal but different in detail.
A series of twelve spectra was defined on forehand by setting a specific voltage sequence on 6 channels of the Variable Function generator. These spectra follow each other up aperiodically and are ring-modulated with a sine-wave for which the frequency is selected at random for every new spectrum from the series. In this way, every new series is permutated in the sense that the time-points and the modulating-frequencies are never identical.
The development over time of this material is caused by a density-curve that was stored on tape and that controlled the speed with which the spectra follow each other up. This density may vary relatively wide within a short period of time, but within the duration of the total of 81/2 minutes it gradually decays to an absolute minimum.
Although the transformation processes added more and more new characteristics to the sounds, causing their initial characteristics to gradually disappear, the density of events that changes over time on the initial tape remains perceptible in all transformations, and plays an important role in the development of the piece as a whole. The most obvious development of the piece however is caused by the way the results from the various transformation processes follow each other up as time-sections.
Overlapping of material-groups never occurs in D.O.F. no.1. The sound-material remained quadraphonic during the entire production process.
It is inherent to the described production process that one ends up with much more sound-material than is used in the eventual piece. For D.O.F. no. 2, I chose to use those results from transformation-processes that remained unused in D.O.F. no. 1.
From these results however, only the last 1 1/2 minutes were selected. Since these sections all originated from the same piece of initial material, they share the same part of the density curve and some other common characteristics.
After various transpositions, the sound-structures were placed in a kind of canon-form in which they overlap each other.
In comparison to D.O.F. no. 1, the initial material for D.O.F. no. 3 is much more static, meaning here that it has no real development in it self. No spectra were defined on forehand as in D.O.F. no.1. The material (of much less timbral complexity) originates in a synthesis-model in which all parameters are selected from limited random sources. From the results, a sound-structure of one minute long with a certain thematic quality was selected. It is exposed in the beginning of the piece.
From this sound-structure, five main groups were produced by means of transpositions and superpositions (Single, Double, Quadra, High Cluster, Low Fifth). These five groups formed the basis for the transformation-processes.
D.O.F. no. 3 is divided into three sections (red, blue, yellow) that each consist of five material groups. These groups are selected from the five main groups in a repetitive sequence, but in every section the material originates from a lower part of the family-tree, by which the sounds recede more and more from the basic material while the piece continues.
In every new section, the overlapping between material-groups is increased.
As in D.O.F. no. 2, for D.O.F. no. 4 I chose to use the results from transformation-processes that remained unused in D.O.F. no. 3. The order in which the material groups appear is illustrated by the purple line in the family tree. Structurally however there is a difference with D.O.F. no. 3 in the sense that one material group is continuously present, while it is accompanied alternatively by the others.