Making Music with Algorithms: A Case-Study System

19 Computer Music Journal, 23:2, pp. 19–30, Summer 1999 © 1999 Massachusetts Institute of Technology. Musicians, perhaps more so than any other group of artists, have always been quick to embrace technology in all its forms. From early attempts at synthesis with the Telharmonium (Roads 1996) to the latest digital-audio workstations (see, for example, Lehrman 1997; Manning 1993), musicians have looked to science to provide them with new and challenging ways of working. One composition method that has benefited greatly from advances in technology is algorithmic composition. Algorithmic composition is by no means new—formal techniques for melody composition date back to at least 1026, when Guido d’Arezzo proposed a scheme that assigned pitches to each vowel sound in a religious text (Loy 1989)—but the advent of affordable and powerful computing resources has meant that more and more people, armed with no more than a little programming knowledge and some musical ideas, have been able to realize their composition algorithms from the comfort of their own desktops. The use of computers as composition generators was pioneered in the mid-1950s by such people as Lejaren Hiller (Hiller and Isaacson 1959), whose 1956 work, The Illiac Suite for String Quartet, is recognized as being the first computer-composed composition. Iannis Xenakis (Xenakis 1960, 1971), although not the first to publish a computer-composed work, had been composing stochastically generated pieces by hand for some time before the premier of The Illiac Suite. Later, Gottfried Koenig developed the Project 1 and 2 composition programs (Koenig 1970a, b). Computer-based algorithmic composition continues the post-war trend toward formalized and systematic composition methods, such as Arnold Schoenberg’s tone-row and Anton Webern’s serialism methods (Roads 1996). Considered thus, it is apparent that the computer is merely a tool for the realization of abstract design constructs, and is best employed as a labor-saving device to free the composer from performing menial calculations by hand. Using a computer, it is possible to preview and test the musical capabilities of many different algorithmic types and judge whether they have the potential to be developed into full-fledged composition systems. This is also the view subscribed to by the authors. Computers in music, and indeed, the algorithmic composition systems themselves, are best thought of as composition tools rather than one-stop music solutions. It was with this in mind that we developed CAMUS 3D, a composition system of our own design that likens the process of music composition to that of pattern propagation. In this article, we introduce the system and show how two classes of algorithms are used to generate musical data.