Acoustics, psychoacoustics and spectral music

The aim of this article is to examine the points at which acoustics, psychoacoustics and what has been called 'spectral music" meet. The motivations behind this bringing together of three more or less barbaric words are to be found in the principle of the spectral approach itself. The tonal system is governed by a set of harmonic rules that embody a compromise between the will to modulate among keys, the system of symbolically notating music, the available set of instruments, certain laws of acoustics, as well as many other concerns. This imposing edifice was patiently constructed by an accumulation of experience and benefited from a slow, cultural maturation. But the bases of this edifice were shaken in the evolution of contemporary music by recent developments in our relation to sound: previously of a fleeting and evanescent, ungraspable nature, sound has been captured and manipulated by way of recording technology. The theory of signals, associated with the computational power of m o d e m computers, has made it possible to analyze sound, to understand its fine structure, and to fashion it at will. The potential musical universe has thus 'exploded' in a certain sense. Sound synthesis opens truly unheard perspectives, extending the act of composition to the sound material itself. The distinctions between note, frequency, timbre, and harmony become fuzzy, or even irrelevant, and accumulated traditional experience finds itself impotent to organize the emerging sound world. After such a shock, new means of formalizing and structuring needed to be defined. Rather than establish a series of arbitrary rules, the spectral