Generative music is a term popularized by Brian Eno to describe music that is ever-different and changing, and that is created by a system.
In 1995 whilst working with SSEYO's Koan software (built by Tim Cole & Pete Cole who later evolved it to Noatikl then Wotja), Brian Eno used & coined the term "Generative Music" to describe any music that is ever-different & changing, created by a system. The term has since gone on to be used to refer to a wide range of music, from entirely random music mixes created by multiple simultaneous CD playback, through to live rule-based computer composition.
Koan was SSEYO's first real-time music generation system, developed for the Windows platform. Work on Koan was started in 1990, and the software was first released to the public in 1994. In 1995 Brian Eno started working with SSEYO's Koan Pro software, work which led to the 1996 publication of his title 'Generative Music 1 with SSEYO Koan Software'.
In 2007 SSEYO evolved Koan into what became Intermorphic Noatikl, and eventually Noatikl itself evolved into Wotja; Wotja X was launched in 2018 for all of iOS, macOS, Windows and Android.
Eno's early relationship with SSEYO Koan and Intermorphic co-founder Tim Cole was captured and published in his 1995 diary A Year with Swollen Appendices.
Many software programs have been written to create generative music.
SSEYO and Intermorphic
The products created by Intermorphic and SSEYO are as follows, in historical order:
- SSEYO Koan Pro (1994-2007), used by Brian Eno to create his hybrid album Generative Music 1. The SSEYO Koan software was created by Pete Cole and Tim Cole of Intermorphic, who re-acquired the Koan technology in 2008. The software was displayed in the London Science Museum's Oramics exhibition (2011-2012) . Koan was superseded by Noatikl in 2007.
- Intermorphic's Noatikl (2007- 2017). Noatikl was described by Intermorphic as "The Evolution of Koan", and was launched in 2007 as a replacement for the no-longer-available Koan. Noatikl is a generative music engine that generates MIDI events in accordance with a rule set that can be manipulated in real-time through a graphical user interface. Noatikl can operate as a Hyperinstrument by responding to incoming MIDI event data, with optional extension through user-supplied Lua scripts. Noatikl is available as a standalone tool for iOS, macOS and Windows, and there are VST and AU plug-ins for desktop music sequencers. Noatikl 1 was released in December 2007. Noatikl 2 was released in May 2012. Noatikl 3 for iOS, macOS and Windows was released in November 2015. Noatikl 3 was superseded by Wotja 2017 in February 2017.
- Intermorphic's Mixtikl (2004-2017), a portable generative music lab and loop mixing system with variants for iOS, iPad, Android, macOS and Microsoft Windows, as well as VST and Audio Unit plug-ins for desktop music sequencers. Mixtikl includes an embedded Noatikl generative music engine and Noatikl editor, and the Partikl modular synthesizer system. Mixtikl 7 for iOS, Android, macOS and Windows was released in November 2015. Mixtikl 7 was superseded by Wotja 4 in February 2017.
- Intermorphic's Tiklbox (2012-2017). Tiklbox was an app for iOS, which used an integrated Noatikl music engine to create ambient generative music in an album context, to assist in relaxation and reflection. Tiklbox 1 was superseded by Wotja 2017 in February 2017.
- Intermorphic's Wotja (2014-present). Wotja is described by Intermorphic as "the consolidation and evolution of Noatikl, Mixtikl, Liptikl, Tiklbox & SSEYO Koan", and was first launched in 2014. Wotja is an application which integrates the Noatikl generative music engine together with the Mixtikl generative mixing engine, the Partikl modular synthesizer and FX framework, the Tiklbox album player, and the Liptikl generative text engine. Wotja can be used to create both a synthesized audio output, or a stream of MIDI events, and incorporates generative text elements. The application's user interface is used to manipulate the underlying components in real-time. Wotja files can be exported and shared as both individual items, or integrated albums of generative content. Wotja is available as a standalone tool for iOS and macOS; versions for Android and Windows are expected to be released in 2018. Wotja 1 was released for iOS in April 2014. Wotja 2017 (also referred to as Wotja 4) for iOS and macOS was released in February 2017. Wotja 2018 was released in January 2018.
- Intermorphic's Wotja X (2018-present). Wotja X is described by Intermorphic as their "new cross-platform generative music app and currently the baby brother to Wotja.". Wotja X uses the same generative music engine (and other engines) as Wotja, and allows sharing of content between the two applications. Wotja 2018 was released in January 2018, with versions launched simultaneously for iOS, macOS, Windows and Android. Intermorphic have stated their intention to work to develop a range of editing interfaces within Wotja X, with the long-term plan of having similar editing capabilities to those of "Wotja" for iOS/macOS; at which point, Wotja X is expected to replace Wotja.
Programs from other sources include the following:
- RoGame Software's Quincy (2014-present), a musical explorer of Life based on the cellular automaton created by John Horton Conway for iOS and macOS. Quincy is a full implementation of Life, capable of generating all possible variations, the common B3/S23 as well as others like HighLife or Seeds.
- IMPROVISOR for AudioCubes IMPROVISOR for Audiocubes, used by Mark Mosher and other electronic music composers. IMPROVISOR and Audiocubes were created by Bert Schiettecatte of Percussa.
- FractMus, developed by Gustavo Díaz-Jerez is a real-time algorithmic music generator.
- Bronze a new format for recorded music that reinterprets the piece on each listening. created by Gwilym Gold and Lexx and released on macOS and iOS
- Tune Smithy, developed by Robert Walker, for Windows generates music real time using a musical construction similar to the Koch snowflake fractal.
- Nodal (2007-present), a graph-based generative composition system for real-time MIDI sequence generation (for macOS and Windows)
- Bubble Harp developed 1997-2011 by Scott Snibbe for the iPad, iPhone, and iPod Touch.
- Bloom developed 2008 by Peter Chilvers together with Brian Eno for the iPhone and iPod Touch.
- Karlheinz Essl's sound environments fLOW (1998-2004) and SEELEWASCHEN (2004)
- Metascore (Sorensen, Brown and Hedemann 2008) supports the generative composition of music to video timing cues.
- MusiGenesis (2005), a generative music program for Windows.
- Lauri Gröhn has developed Synestesia software that generates music (midi file) from any photos in a few seconds.
- Many algorithmic music projects are also considered to be generative (see algorithmic.net for some of them).
- Modern generative music games such as Rez have been considered generative in character.
- Sergio Maltagliati generative music software .
- Kepler's Orrery, an interactive gravity simulator that generates music, developed in 2007 as an open-source Java project and ported to the iPhone in 2009.
- Dub Cadet, is the generative arduino based software and hardware interface for creating music through rotational motion developed by Noah Hornberger in 2012.
- 'Scape' (software) app developed by Brian Eno and Peter Chilvers for the iPad in 2012.
- Capture is a generative rock band  based on emergent and procedural software. Capture generates pop music, lyrics, images and videos 24/7 on the web. (see chatonsky.net for more info).
- Loligo image-based development environment for generative music, developed 2014 by Vanja Cuk
- Generative a MaxMSP-based application designed to create continually evolving soundscapes and drones, second version released in 2015 by Michael Sweeton.
- StyleMachineLite a MAX for Live application by Canadian company Metacreative, released in 2015.
- Staggered Laboratories is a generative development project focused on melodic compositions. The stack includes homegrown software that produces endless 24/7 audio streams in the pop and electronica genres.
- Quasi Art - automatic program for generation quasi music (algorithm by Lois Alexandre, released 2016). The program creates unimaginable and bizarre orchestral melodies created programmatically using the built-in synthesizer in realtime.
There are four primary perspectives on generative music (Wooller, R. et al., 2005) (reproduced with permission):
Music composed from analytic theories that are so explicit as to be able to generate structurally coherent material (Loy and Abbott 1985; Cope 1991). This perspective has its roots in the generative grammars of language (Chomsky 1956) and music (Lerdahl and Jackendoff 1983), which generate material with a recursive tree structure.
Music generated by a system component that has no discernible musical inputs. That is, "not transformational" (Rowe 1991; Lippe 1997:34; Winkler 1998). The Wotja software by Intermorphic, and the Koan software by SSEYO used by Brian Eno to create Generative Music 1, are both examples of this approach.
Music generated by processes that are designed and/or initiated by the composer. Steve Reich's It's Gonna Rain and Terry Riley's In C are examples of this (Eno 1996).
Non-deterministic music (Biles 2002), or music that cannot be repeated, for example, ordinary wind chimes (Dorin 2001). This perspective comes from the broader generative art movement. This revolves around the idea that music, or sounds may be "generated" by a musician "farming" parameters within an ecology, such that the ecology will perpetually produce different variation based on the parameters and algorithms used. An example of this technique is Joseph Nechvatal's Viral symphOny: a collaborative electronic noise music symphony created between the years 2006 and 2008 using custom artificial life software based on a viral model.
- Brian Eno, who coined the term generative music, has used generative techniques on many of his works, starting with Discreet Music (1975) up to and including (according to Sound on Sound Oct 2005) Another Day on Earth. His works, lectures, and interviews on the subject have done much to promote generative music in the avant-garde music community. Eno used SSEYO's Koan generative music system (created by Pete Cole and Tim Cole of Intermorphic), to create his hybrid album Generative Music 1 (published by SSEYO and Opal Arts in April 1996), which is probably his first public use of the term generative music.
- Lerdahl and Jackendoff's publication described a generative grammar for homophonic tonal music, based partially on a Schenkerian model. While originally intended for analysis, significant research into automation of this process in software is being carried out by Keiji Hirata and others.
- In It's Gonna Rain, an early work by contemporary composer Steve Reich, overlapping tape loops of the spoken phrase "it's gonna rain" are played at slightly different speeds, generating different patterns through phasing.
- A limited form of generative music was attempted successfully by members of the UK electronic music act Unit Delta Plus; Delia Derbyshire, Brian Hodgson and Peter Zinovieff, in 1968. However, its use would only be popularized later on.
- Artística de Valencia, After The Net, 5 - 29 June 2008, Valencia, Spain: catalogue: Observatori 2008: After The Future, p. 80
- Biles, A. 2002a. GenJam in Transition: from Genetic Jammer to Generative Jammer. In International Conference on Generative Art, Milan, Italy.
- Chomsky, N. 1956. Three models for the description of language. IRE Transcripts on Information Theory, 2: 113-124.
- Collins, N. 2008. The analysis of generative music programs. Organised Sound, 13(3): 237-248.
- Cope, D. 1991. Computers and musical style. Madison, Wis.: A-R Editions.
- Dorin, A. 2001. Generative processes and the electronic arts. Organised Sound, 6 (1): 47-53.
- Eno, B. 1996. Generative Music. http://www.inmotionmagazine.com/eno1.html (accessed 26 February 2009).
- Essl, K. 2002. Generative Music. http://www.essl.at/bibliogr/generative-music.html (accessed 22 Mar 2010).
- García, A. et al. 2010. Music Composition Based on Linguistic Approach. 9th Mexican International Conference on Artificial Intelligence, MICAI 2010, Pachuca, Mexico. pp. 117-128.
- Intermorphic Limited History of Noatikl, Koan and SSEYO (accessed 26 February 2009).
- Lerdahl, F. and R. Jackendoff. 1982. A generative theory of tonal music. Cambridge, Mass: MIT Press.
- Lippe, C. 1997. Music for piano and computer: A description. Information Processing Society of Japa SIG Notes, 97 (122): 33-38.
- Loy, G. and C. Abbott. 1985. Programming languages for computer music synthesis, performance and composition. ACM Computing Surveys, 17 (2): 235-265.
- Nierhaus, G. Algorithmic Composition - Paradigms of Automated Music Generation. Springer 2009.
- Rowe, R. 1991. Machine Learning and Composing: Making Sense of Music with Cooperating Real-Time Agents. Thesis from Media Lab. Mass.: MIT.
- Viral symphOny is downloadable for free at www.archive.org
- Winkler, T. 1998. Composing Interactive Music. Cambridge, Massachusetts: MIT Press.
- Wooller, R., Brown, A. R, et al. A framework for comparing algorithmic music systems. In: Symposium on Generative Arts Practice (GAP). 2005. University of Technology Sydney.