Timbre Composition in Electroacoustic Music

Simon Emmerson, Simon Emmerson

• Publisher: Routledge
• Year: 2019
• ISBN:
  9781134358779
• Edition: 1
• Topic: Media & Performing Arts
• Subtopic: Theatre

First Published in 1994. The contributions to this collection have been selected to define a range of interests from the technical, aesthetic, cognitive and compositional spheres. The book addresses the continuing need for musicologists, psychologists, composers and listeners to enter into a creative dialogue with designers and builders, who are usually programmers in the contemporary world. The collection as a whole will help to demonstrate the great potential for exchange between the multidisciplinary approaches to music.

Ways and Means

Micro-Time Sonic Design and Timbre Formation

Agostino Di Scipio
LșAquila, Italy

This article outlines a particular mode of composition wherein timbre emerges from micro-level processes of sonic design, on the basis of discrete-time microstructural representations of sound. This approach is characterised in terms of models of detailed sonic design and is described as a unique instance of an indeterministic style of creative thinking in electroacoustic music composition.

The discussion includes examples drawn from early electroacoustic music works (Pousseur, Xenakis, Brim, Stockhausen) and more recent work in computer music, including the author’s own experience with methods of granular synthesis. Finally, we examine the notion of timbre as conceived in the approach under observation, and suggest that timbre composition fosters a profound change of compositional paradigm; indeed, it can challenge a clear-cut dualism between materials and form, and transform the conception itself of musical form into one of processes of timbre formation through time.

KEY WORDS: music composition as sonic design, models of sound materials, microstructural representations of sound, granular synthesis, algorithmic synthesis

Basic Assumptions and Premises

The development of computer music technology and musical acoustics and psychoacoustics has greatly expanded the possibilities, first raised by the advent of electroacoustic music studios, for a thorough-going music of timbre. The introduction of computer-based tools and digital devices, being more than a mere enlargement of the technical resources, represents the emergence of new conceptual tools and a profound reworking of the composer’s conception of the materials and forms of his/her art.

Indeed, any technological upheaval in art comes with, or is preceded (and required) by, a shift in cognitive skills and expressive possibilities experienced by artists. Similarly, the practice of a sonic art (Wishart, 1985) reflects profound changes in the notions of musical material and musical form, as well as in the relation between them, the relation of language to material (Emmerson, 1986). The core of these changes is bound up in the reformulation of the concept of timbre; as we will observe later, timbre appears as the global character of something deliberately designed, that is, as the perceptual dynamical properties of a composed, formed sound-object.

The aim of the present discussion is to focus on a kind of compositional approach which, though fundamental to electroacoustic and computer music, represents a novel and relatively unexplored mode of creative musical thinking; it involves the designing of sound-objects and more extended musical structures by means of processes operating at the level of the micro-time behavior of sound. The design strategies adopted in this approach can be thought of as strategies of microstructural time modelling of sound. Using processes grounded on microstructural discrete-time representations of sound, a composer can shape the timbral morphology of music by organising innumerable particles, or discrete sonic units, in time. Granular synthesis is a well-known example, and later I will briefly introduce and discuss aspects of my own methods of granular synthesis. However we will soon observe that the definition of micro-time sonic design is generalisable, in that it captures a unique perspective shared by different processes of timbre composition.

In the following sections, examples of micro-time processes of composition will be drawn from early works of electroacoustic music and more recent computer-based research. After, I will discuss some of the assumptions and results of this creative practice, in order to draw conclusions concerning the underlying relation of timbre to musical form. The implicit thesis throughout the discussion is that timbre composition, especially when it involves microstructural representations of sound, escapes the classical separation of sound material and musical form inherited from vocal and instrumental music. This separation is still persisting in most electroacoustic music approaches and is evident in the computer implementation of compositional models which separate composing-1he-sound from composing-with-sound, sound from structure (Truax, 1990b). While these models consolidate the drastic distinction of compositional competence and actions bearing on the sound material versus competence and actions bearing on the formal articulation of music, actually the most peculiar aspect of timbre composition involves the possibility of blurring this cognitive separation. A more thorough analyis of such music-theoretical issues is taken in a companion article (Di Scipio, 1993b).

Historical Precedents of Micro-time Sonic Design

The idea of composing music by microstructural processes was first put forth in the early years of electroacoustic music. In the realisation of works like Pousseur’s Scambi (1957), Xenakis’ concrète PH (1959), Brim’s computer music composition Infraudibles (1969) and Stockhausen’s Kontakte (1960), the sound material was designed according to models of the composers’ own invention, largely regardless of pre-established acoustic models; the works cited involved micro-level processes aimed at handling large numbers of minimal sonic units.

Scambi, the many versions of which were the result of different layerings of multiple musical structures, utilised a unique sound processing device, dubbed selecteur d’amplitudes; its function was to output those portions of an input signal above a given amplitude threshold, thus removing any signal below the threshold. By supplying inharmonic sounds and electronically generated noise to this device and manually controlling the amplitude threshold, Pousseur generated discontinuous streams of short noise-bursts of variable temporal density and spectral properties (Pousseur, 1959).¹ A similar technique had been already used by Madema in his Syntaxis (1957).

¹ The textures of sound generated using the selecteur d’amplitudes were, however, smoothed out in a further stage of elaboration, involving band-pass filtering and delay lines. The device was designed and built in the Studio di Fonologia in Milan by Dr, A. Lietti; its process may be thought of as the inverse of clipping a signal.

One of the most interesting techniques of sound production utilised for the tape part of Kontakte, consisted of organising sequences of squared impulses. The composer used serial permutational laws to determine the delay between impulses and the impulse amplitude. Once recorded on tape, these sequences of impulses were played back at various speeds, thus obtaining either discrete rhythmical events or continuous, broad-band textures of sound (Stockhausen, 1963, pp. 211–221). In concrète PH, Xenakis created clouds of sound droplets by decomposing the tape recording of a concrète sound-object (the noise of smouldering charcoal) into tiny splices of tape that he reorganised in patterns of statistical density. (The task was accomplished exclusively by means of manual tape editing.) Finally, Herbert Brün in Infraudibles used computer programs to create sound structures by linking single-period wavetables, each with its own waveform but mutually phase-coherent (Brün, 1969).

Pousseur himself dedicated a chapter of his Fragments thèoriques I sur la musique expérimentale to the practical and theoretical implications of composing music at the level of the temporal microstructure of sound (1970, pp. 138–157). The chapter included a cogent and constructive critique of the somewhat mystical line found in Stockhausen’s Einheit der muzikalischen Zeit (1963) - or the unity of time in electronic music, where both the micro-world of a single sound and the macro-world of extended musical forms can be shaped by means of the same laws of numerical proportion.² Pousseur also observed (1970, p. 138 and 140) that other techniques of micro-time sonic design had been used in the composition of the tape part of Berio’s Perspectives and Ligeti’s Artikulation.

² If such was Stockhausen’s programmatic position, it is clear, however, that in Kontakte there is more than just an idealistic projection of symmetry between micro and macrostructure - both were in fact further enriched by compositional decisions based on perception and individual taste (Pousseur, 1970, p. 146).

With the exception of these early works and important later endeavors by Xenakis and Brün, discrete-time approaches have only rarely been adopted until recent progress in computer music and representations of the musical signal provided support for more thorough and systematic research.

Computer-based Micro-time Sonic Design

Today, processes of micro-time sonic design operate from a number of different musical perspectives; among the most interesting, I would mention algorithmic synthesis (Koenig, 1987; Xenakis, 1991; Berg, 1985; Manzolli, 1993) and methods based on granular representations of sound - especially quasi-sychronous and asynchronous granular synthesis a...

Table of contents

• Cover
• Copyright
• Contents
• Preface
• Historical Analysis
• Aesthetics and Psychology
• Ways and Means
• Index