The Computer Music Tutorial (The MIT Press)

Book Preface

With the use of computers and digital devices, the processes of music com­position and its production have become intertwined with the scientific and technical resources of society to a greater extent than ever before. Through extensive application of computers in the generation and processing of sound and the composition of music from levels of the microformal to the macroformal, composers, from creative necessity, have provoked a robust interdependence between domains of scientific and musical thought. Not only have science and technology enriched contemporary music, but the converse is also true: problems of particular musical importance in some cases suggest or pose directly problems of scientific and technological im­portance, as well. Each having their own motivations, music and science depend on one another and in so doing define a unique relationship to their mutual benefit.

The use of technology in music is not new; however, it has reached a new level of pertinence with the rapid development of computer systems. Modern computer systems encompass concepts that extend far beyond those that are intrinsic to the physical machines themselves. One of the distinctive attributes of computing is programmability and hence program­ming languages. High-level programming languages, representing centuries of thought about thinking, are the means by which computers become ac­cessible to diverse disciplines.

Programming involves mental processes and rigorous attention to detail not unlike those involved in composition. Thus, it is not surprising that composers were the first artists to make substantive use of computers. There were compelling reasons to integrate some essential scientific knowledge and concepts into the musical consciousness and to gain competence in areas which are seemingly foreign to music. Two reasons were (and are) particularly compelling: (1) the generality of sound synthesis by computer, and (2) the power of programming in relation to the musical structure and the process of composition.

Although the traditional musical instruments constitute a rich sound space indeed, it has been many decades since composers’ imaginations have con­jured up sounds based on the interpolation and extrapolation of those found in nature but which are not realizable with acoustical or analog electronic instruments. A loudspeaker controlled by a computer is the most general synthesis medium in existence. Any sound, from the simplest to the most complex, that can be produced through a loudspeaker can be synthe­sized with this medium. This generality of computer synthesis implies an extraordinarily larger sound space, which has an obvious attraction to com­posers. This is because computer sound synthesis is the bridge between that whic? can be imagined and that which can be heard.

With the elimination of constraints imposed by the medium on sound production, there nonetheless remains an enormous barrier which the com­poser must overcome in order to make use of this potential. That barrier is one of lack of knowledge-knowledge that is required for the composer to be able to effectively instruct the computer in the synthesis process. To some extent this technical knowledge relates to computers; this is rather easily acquired. But it mostly has to do with the physical description and percep­tual correlates of sound. Curiously, the knowledge required does not exist, for the most part, in those areas of scientific inquiry where one would most expect to find it, that is, physical acoustics and psychobiology, for these disciplines often provide either inexact or no data at those levels of detail with which a composer is ultimately most concerned. In the past, scientific data and conclusions were used to try to replicate natural sounds as a way of gaining information about sound in general. Musicians and musician­scientists were quick to point out that most of the conclusions and data were insufficient. The synthesis of sounds which approach in aural complexity the simplest natural sound demands detailed knowledge about the temporal evolution of the various components of the sound.

Physics, psychology, computer science, and mathematics have, however, provided powerful tools and concepts. When these concepts are integrated with musical knowledge and aural sensitivity, they allow musicians, scien­tists, and technicians, working together, to carve out new concepts and physical and psychophysical descriptions of sound at levels of detail that are of use to the composer in meeting the exacting requirements of the ear and imagination.

As this book shows, some results have emerged: There is a much deeper understanding of timbre, and composers have a much richer sound palette with which to work; new efficient synthesis techniques have been discovered and developed that are based upon modeling the perceptual attributes of sound rather than the physical attributes; powerful programs have been developed for the purposes of editing and mixing synthesized and/or digi­tally recorded sound; experiments in perceptual fusion have led to novel and musically useful research in sound source identification and auditory images; finally, special purpose computer-synthesizers are being designed and built. These real time performance systems incorporate many advances in knowledge and technique.