Algorithmic Music

Algorithmic Music

Generative Music

“Though I may have the pleasure of discovering musical processes and composing the musical material to run through them, once the process is set up and loaded it runs by itself.” in Schwarz, K. R. (1981). Steve Reich: Music as a Gradual Process Part II. Perspectives of New Music, 225–286.1

Steve Reich’s quote summarizes the essence of generative music as a discovery of musical process and then letting the system run by itself. Randomness is one of the process elements that enters into the equation.

Brian Eno and Steve Reich

“I truly believe that our grandchildren will one day say to us: do you mean you really listened to the same piece over and over again?” Brian Eno (1996)2

“I’ve always been lazy I guess. So I’ve always wanted to set things in motion that would produce far more than I had predicted” (Brian Eno 1996)

Brian Eno’s carrier3 spans a long musical arc taking off in the seventies (co-founder of Roxy Music) up to today with innovative multimedia projects. I’m going to focus on his contributions to algorithmic music and his links with Steve Reich. He has been at the forefront of creating and releasing music under different formats that allows the listener to experience the non linearity of generative music.

It’s worth quoting Brian Eno, the musician who owns the domain name generativemusic.com and coined4 the term, from this The Guardian interview5 (2010):

“I came out of this funny place where I was interested in the experimental ideas of Cornelius Cardew, John Cage and Gavin Bryars, but also in pop music. Pop was all about the results and the feedback. The experimental side was interested in process more than the actual result – the results just happened and there was often very little control over them, and very little feedback. Take Steve Reich. He was an important composer for me with his early tape pieces and his way of having musicians play a piece each at different speeds so that they slipped out of synch. But then when he comes to record a piece of his like, say, Drumming, he uses orchestral drums stiffly played and badly recorded. He’s learnt nothing from the history of recorded music. Why not look at what the pop world is doing with recording, which is making incredible sounds with great musicians who really feel what they play. It’s because in Reich’s world there was no real feedback. What was interesting to them in that world was merely the diagram of the piece, the music merely existed as an indicator of a type of process. I can see the point of it in one way, that you just want to show the skeleton, you don’t want a lot of fluff around it, you just want to show how you did what you did. As a listener who grew up listening to pop music I am interested in results. Pop is totally results oriented and there is a very strong feedback loop. Did it work? No. We’ll do it differently then. Did it sell? No. We’ll do it differently then. So I wanted to bring the two sides together. I liked the processes and systems in the experimental world and the attitude to effect that there was in the pop, I wanted the ideas to be seductive but also the results.

Steve Reich’s tape works that directly influenced6 Brian Eno and led him to explore and establish the principles of ambient music. He “became interested in creating musical systems that produced music of infinite length that never repeated itself rather than linear works that had a fixed structure and time frame”.7 The company SSEYO was founded in 1992 and developed Koan, a generative music engine. Brian Eno received a copy in 1995 that led him to come up with the term “generative music”.

Algorithmic Music

Generative music falls under the larger category of the word algorithm that can be understood as a well-defined set of operations or rules but “algorithmic music” extends to:

“a rich field of activity, defined by the urge to explore and/or extend musical thinking through formalized abstractions. In the process of making music as … algorithms, we express music through formal systems of notation, taking a view of music as the higher order interplay of ideas.” 8

Minimal music form the 60ties by Glass and Reich is algorithmic in nature although manually composed and having a start and finishing point (e.g. Clapping Music, Piano Phase). Continuum for harpsichord (1968) from Ligeti, uses “rigorous algorithmic procedures” on the pitch and rhythmic structures “permitting complex rhythmic juxtapositions and transformations”.

Examples of Brian Eno’s Generative Works

Ambient 1: Music for Airports (1978)

“I worked on things like [algorithmic music] for a while: Music for Airports and Discreet Music were examples, but what they represented were recordings of these processes in action. What I really wanted to do was to be able to sell the process to somebody, not just my output of it.” (Brian Eno, Dredge 2012)

Discreet Music (1975)

The back cover of the Discreet Music LP features an elaborate drawing of the tape delay methodology:

discmusic

Generative Music 1 (1996)

Brian Eno released this music on a floppy disc for the for Koan Pro system in 1996.

Will Wright and Brian Eno - Generative Systems (in computer games 2006)

Generative Music Apps

The following apps released for iOS (and for some on Android) seem like the logical conclusion to the difficulties of distributing algorithmic, generative ever changing and repeating music on a support. Fixing them on vinyl or CD was always a dead end. In “In Algorithmic Music for Mass Consumption and Universal Production9 Yuli Levtov states that one of the key issues for reaching a larger public or in some instances any public is one of the main issues of distributing algorithmic music. Brian Eno in collaboration with Peter Chilvers released several generative apps offering the user to influence different generative parameters.

Bloom (2008 by Brian Eno & Peter Chilvers)

Trope (2009 by Brian Eno & Peter Chilvers)

Air (2009 by Brian Eno & Peter Chilvers)

Scape (2012 by Brian Eno & Peter Chilvers)

Quarta (2015 by Brian Eno & Peter Chilvers)

Bloom: 10 Worlds (2018 by Brian Eno & Peter Chilvers)

Bloom Open Space VR installation (2018 by Brian Eno & Peter Chilvers)

In the methodology section the reader can find examples of generative and semi-generative music I created and further explore the distinction and links between adaptive audio and generative music.

Aleatoric Music

“Aleatoric music, or aleatory music or chance music (from the Latin word alea, meaning dice) is music in which some element of the composition is left to chance."10

is sometimes

“the pool of possible outcomes is so large that any waltz you generate with the dice and actually play is almost certainly a waltz never heard before. If you fail to preserve it, it will be a waltz that will probably never be heard again”.10

Music of Changes by John Cage (1951)

Based on an ancient Chinese text (I Ching) to generate random numbers for tempo, dynamics, note duration.

Klavierstück XI by Karlheinz Stockhausen (1956)

19 musical fragments that have to be played in a particular order particular but the musician can start at any place.

Pithoprakta by Iannis Xenakis (1956)

Uses gas molecules. It uses physical or mathematical principles and is called called stochastic music.

In C by Terry Riley (1964)

Riley suggests “a group of about 35 is desired if possible but smaller or larger groups will work”.A series of short melodic fragments, In C is often cited as the first minimalist composition.


  1. Schwarz, K. R. (1981). Steve Reich: Music as a Gradual Process Part II. Perspectives of New Music, 225–286. ↩︎

  2. http://www.medienkunstnetz.de/works/generative-music-1/ ↩︎

  3. brian-eno.net for recent ambient music projects; generativemusic.com for his apps developed together with Peter Chilvers. ↩︎

  4. Brown, P. (2005). Is the Future of Music Generative? Music Therapy Today (Online), 6, 215–274. ↩︎

  5. Morley, P. (2010). On gospel, Abba and the death of the record: an audience with Brian Eno. The Guardian. https://www.theguardian.com/music/2010/jan/17/brian-eno-interview-paul-morley (highlights are mine)) ↩︎

  6. Dean, R. T. (2018). The Oxford handbook of algorithmic music. Oxford University Press. ↩︎

  7. ibid. p. 223 ↩︎

  8. ibid. p. 4 ↩︎

  9. ibid. p. 21 ↩︎

  10. Gardner, Martin. The Colossal Book of Mathematics: Classic Puzzles, Paradoxes, and Problems: Number Theory, Algebra, Geometry, Probability, Topology, Game Theory, Infinity, and Other Topics of Recreational Mathematics. New York: W.W. Norton and Company, Inc., 2001. Print. ↩︎