Music Out of Nothing? A Rigorous Approach to Algorithmic Composition by Iannis Xenakis vorgelegt von Peter Hoffmann Von der Fakultät I - Geisteswissenschaften der Technischen Universität Berlin zur Erlangung des akademischen Grades Dr. phil. genehmigte Dissertation Promotionsausschuss: Vorsitzender: Prof. Dr. Stefan Weinzierl Berichter: Prof. Dr. Christian Martin Schmidt Berichter: Prof. Dr. Helga de la Motte-Haber Tag der wissenschaftlichen Aussprache: 29.04.2009 Berlin 2009 D 83 Music Out of Nothing? A Rigorous Approach to Algorithmic Composition by Iannis Xenakis Peter Hoffmann October 11, 2009 “Perhaps we have grown too accustomed to the idea that it is necessary to exist. I think there is another way but I cannot see clearly, I cannot yet say what it is. There may be another reason for our life, our action than to strive for immortality, power or the jus- tification of existence [...] There must be other reasons. [...] [One] may die and disappear but that applies only to the individual. But not . ” (Iannis Xenakis, 29.05.1922–04.02.2001, in his 1980 conversation with B´alint Andr´as Varga.) 4 Next page: The sensational discovery by Rudolf Pfenninger and Oskar Fischinger (photo) in the 1930s that sound can be arbitrarily invented by “paint- ing” it on the optical sound track of a film strip (instead of recording and pro- cessing it) is reflected in a headline reading “Music out of Nothing” presented as the title of a short introductory prelude to the film “Barcarole” by Rudolf Pfen- niger, a puppet animation film with a synthetic optical sound track ([Goe98], [Mor93]). Iannis Xenakis, sixty years later, goes one step further. He does not define the sound signal by painting but lets it come into being by probability fluctuations of stochastic processes, creating sound from silence, “out of noth- ing”. But in doing so, does he really create a “Music out of Nothing”? 5 Figure 1: Oskar Fischinger’s: “Music Out of Nothing” 6 Abstract GENDY3 (1991) by Iannis Xenakis (1922-2001) is a piece of computer generated music. But it is more than just “computer music”. GENDY3 is the culmination of Xenakis’ lifelong quest for an “Automated Art”: a music entirely generated by a computer algorithm. Being a radical instance of a pure algorithmic composition, GENDY3 is, in a precise mathematical sense, a computable music: every aspect of its sonic shape is defined by an algorithmic procedure called “Dynamic Stochastic Synthesis” (“G´en´eration Dynamique Stochastique”, or GENDYN for short). The GENDYN Project, started by the author in 1995/96 with a research at CEMAMu, then the composer’s research center near Paris, exploits this com- putability for developing and documenting the GENDYN concept, in order to understand its various ramifications and to make it accessible for further re- search and production. To this end, the author implemented Dynamic Stochas- tic Synthesis in a new program called the “New GENDYN Program” which, in addition to “recomposing” GENDY3 in real time, makes it possible to inspect and control the algorithmic composition process, thereby opening up new per- spectives both in Computational Musicology and in computer music creation. For music analysis purposes, GENDY3 has been completely resynthesized. The simulation of the genesis of GENDY3 “in vitro” made possible by the New GENDYN Program permits the systematic exploration of the “decision space” of the composition model, contributing to a deeper understanding of both its potentials and limitations, and the complex interaction between “material requirements” and compositional freedom within which the composer navigated. The study of the GENDYN compositions provokes many fundamental ques- tions about computing, listening and understanding, of creation, interaction and computer music aesthetics. It is shown that Xenakis, unlike many computer music composers, had no ambition whatsoever to emulate traditional musical thinking with the computer. Instead he realized his sonic vision in an abstract physical model of sound pressure dynamics yielding higher-order musical struc- tures as emergent epiphenomena. This unusual approach addresses the medium of electroacoustic algorithmic music, i.e. the physics of sound, as well as the computability of sound as subjects of artistic creation. This approach seems to the author to be of a higher value for the foundation of a “true” computer art than the widespread ambition to emulate human creativity by computers and to build up an artificial brave new world of music. 7 8 Preface This is the documentation and discussion of a research project in algorithmic computer music, started in August 1995 with a research in Paris, in the frame- work of a dissertation at the Technische Universit¨at Berlin. Its scope is the latest achievement by Iannis Xenakis (1922-2001) in composing music with the com- puter at his institute CEMAMu (“Centre d’´etudes de Mathematique et Automa- tique Musicales”1) in Paris. The composer called his new computer composition method “Dynamic Stochastic Synthesis”. It is a rigorous algorithmic procedure for not only composing the macro-structure of a composition (i.e. on the level of duration and pitch) but also the micro-structure of sound (i.e. on the level of the digital sample). GENDYN is the name Xenakis gave to his computer program(s) realizing the stochastic synthesis, short for the French term “GEN´eration´ DY- Namique”. The original program was written in BASIC by the composer himself at CEMAMu, Paris, with the assistance of Marie-H´el`ene Serra. In 1991, a single run of this program, called “GENDY301”, generated GENDY3, a piece of about 20 minutes. It was later released on CD (NEUMA 450-86). In the aftermath, Xenakis tried to extend the program to include additional time-variant effects by making some parameter settings of GENDYN’s stochastic processes time- dependent. This resulted in a second piece S709, premiered in 1994, which is beyond the scope of this study. The “GENDYN Project”, the subject of this study as I would like to call it, is a project that takes Xenakis’ legacy in algorithmic music creation and tries to complete it in a way Xenakis either did not care or has not been able to do during his lifetime. First, the idea is to keep GENDYN on top of current computer technology in order to ensure its usability for the present and future. The result of this was what I baptized the “New GENDYN Program”, a com- plete new implementation of Xenakis’ program using C++ for synthesis and Visual Basic for the graphic user interface, on the Windows platform. Second, using the tools constructed in the first step, the GENDYN project aims at un- derstanding the richness of Xenakis’ unique approach to computer creation, its various implications and ramifications in the fields of music aesthetics, analysis and production. Third, the idea is to feed back the results of steps one and two to the computer music community for artistic use. Xenakis of course was the first to be offered the New GENDYN Program but he declined, either on the basis of personal conviction or due to misunderstandings on his or my side. But other composers have used it or are interested in using it, similar to what happened to Xenakis’ early ST-program (1958-62) which Xenakis was proud of 1The English equivalent is Centre for Mathematical and Automated Music, a name actually given to a sister institution at Bloomington University, Indiana, led by Xenakis in 1967-72. 9 10 handing out to universities and research centers. One aspect of the GENDYN Project, therefore, is to reproduce and study Xenakis’ original composition GENDY3. Another aspect is to go further and to systematically explore the sonic space of GENDYN by controlling the pa- rameters of synthesis while listening to the aural result. This makes the New GENDYN Program, in addition to being a customized tool for the analysis of a single musical piece, a generic “stochastic composition instrument”, much in the sense of interactive computer composition. It follows from the above considerations that the nature and the goals of the project are actually double-sided: one is “scientific”: the musicological anal- ysis of GENDY3, a specific piece of computer generated music. The other is “artistic”: to preserve Stochastic Synthesis as a “composition instrument” good for creating new computer music. These two aspects, retrospective analysis and prospective development are two sides of the same coin. If we are interested in a compositional procedure and the music made by it, both from a scientific and an artistic point of view, its analytical as well as its productive aspects prove to be mutually enlightening. The (pre-) history of this project dates back to late 1991, when I heard the sounds of the Dynamic Stochastic Synthesis for the first time. Xenakis’ composition GENDY3, premiered at the Rencontres Internationales de Musique Contemporaine de Metz in November 1991, was broadcast by Sender Freies Berlin in the framework of a program covering the festival’s most prominent events. This was a startling experience. Never had I heard sounds like this before. Not only was it the richness and the strangeness of the sounds, but also the fact that these sounds were “generated by the computer”. They sounded totally different from what I was used to associate with “computer generated sound”. Never had I experienced a computer music so brute, fresh and immediate. As I later learned, GENDYN sound is immediate indeed: all standard means of transmission (score, instruments, microphones, tape) are bypassed as the music is digitally composed by a computer “direct-to-disk”. Of course, the music came from a DAT tape over the air, but it felt as if my loudspeakers were driven by a strange force governed by rules that were at the same time alien and familiar — an experience which maybe is rather typical for listening to Xenakis’ music in general.