Algorithmic composition

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Algorithmic composition is the technique of using algorithms to create music.

Algorithms (or, at the very least, formal sets of rules) have been used to compose music for centuries; the procedures used to plot voice-leading in Western counterpoint, for example, can often be reduced to algorithmic determinacy. The term is usually reserved, however, for the use of formal procedures to make music without human intervention, either through the introduction of chance procedures or the use of computers. There is a radical distinction (both in terms of philosophy and the in the heard result) between composers who use indeterminate (e.g. stochastic) procedures to compose music and those who use routines which produce deterministic results given a fixed input into the algorithm.

Many algorithms that have no immediate musical relevance are used by composers as creative inspiration for their music. Algorithms such as fractals, L-systems, statistical models, and even arbitrary data (e.g. census figures, GIS coordinates, or magnetic field measurements) are fair game for musical interpretation. The success or failure of these procedures as sources of "good" music largely depends on the mapping system employed by the composer to translate the non-musical information into a musical data stream.

Composers known for their use of algorithmic procedures:

Algorithmic techniques have also been employed in a number of systems intended for direct musical performance, with many using algorithmic techniques to generate infinitely-variable improvisations on a predetermined theme. An early example was Lucasfilm Games' 1982 computer game Ballblazer, where the computer improvised on a basic jazz theme composed by the game's musical director. A more advanced implementation of this is present in the music subsystem of Microsoft's Xbox games console - the game plays variations on a human composer's theme, but varies its improvisations based on real-time events in the game (so, for example, the music sounds more staccato and dramatic during fight scenes, but is gentler and more mellow afterward). The effect has been seen in many video-games since the Nintendo 64, the first system with a large enough memory and fast enough ROM retrieval methods to make such a change in the flow and sound of the music possible. One of the first to adopt such sound was The Legend of Zelda: Ocarina of Time where approaching important areas raised the volume and pitch of the sound. Another games of note is Fable on the Xbox for similar uses of sound. Similar systems were also used in games like Command & Conquer: Generals, Splinter Cell and Freedom Fighters.

Similar generative music systems have caught the attention of noted composers. Brian Eno has produced a number of works for the SSEYO's Koan generative music system, which produces ambient variations for web-pages, mobile devices, and for standalone performance. SSEYO's miniMIXA software (2005) allows users of mobile devices such as smartphones to create algorithmic music 'on-the-fly'. The copyright status of these "generative" works is unclear, although the original "composition" is supplied by the composer and the "performance" is largely the result of the user's computer's own algorithms. However, MusiGenesis (see external link below), an algorithmic composition program based on Richard Dawkins' Blind Watchmaker program, makes no ownership claims on music created by the program.

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Samples of algorithmic music

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External links

  • algorithmic.net - a lexicon of systems and research in computer aided algorithmic composition
  • Realtime Composition Tools - generative computer programs for composition, live performance and sound design by Karlheinz Essl
  • MusiGenesis - generative music software that uses applied evolutionary theory to "grow" music; for musicians and non-musicians alike
  • Synestesia - music generated from any pictures in a few seconds; software developed by metacomposer Lauri Gröhn
  • SSEYO Koan Pro - SSEYO's Koan Pro generative music authoring tool, as used by Brian Eno to create 'Generative Music 1'. The Koan engine is used within SSEYO's miniMIXA program for mobile devices.
  • rand()% is a real-time generative internet radio station.
  • Randomusic is a computer program that generates music sounding like human improvisations in the avant-garde genre of classical music. The site has samples with piano and cello you can listen to.
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See also

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