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BOL PROCESSOR is a program initiated by Bernard Bel for music composition and improvisation with real-time MIDI, MIDI file, Csound, and text output options. The earliest implementation of Bol Processor (BP1) on an Apple IIc computer dating back to 1981, was an expert system used by Jim Kippen for modelling improvisational processes by tabla players in North India — read article (1992) and interview.
Bol Processor produces music with a set of rules (a compositional grammar) and/or text scores that can be typed in, captured from a MIDI instrument or imported from MusicXML scores. These rule sets are similar to the formal grammars (context-free, context-sensitive, etc.) used in computer science to define machine-readable languages.
As a compositional tool, Bol Processor (BP2) has been successful at modelling music of many styles including Western classical music, serial music, contemporary art music including minimalism, and Indian classical music. After the implementation of its Csound interface, BP2 won the Bourges 1997 international award (ex aequo with Cecilia) in the category of computer-aided composition and realisation software.
Bol Processor BP2 had begun as a shareware application for Macintosh computers developed by Bernard Bel with the help of Srikumar Karaikudi Subramanian. In the Spring of 2006, Anthony Kozar joined the venture and open-sourced the program with the hope that a community of developers will come together to port it to other platforms and continue to enhance its facilities for music-making. Porting BP2 to Mac OS X was finished in June 2007 by Anthony Kozar.
Bol Processor BP3 introduced new features owing to its closer association with Csound. Essential domains of musicology bearing relevance to computer music are addressed on this site, among which the issue of microtonality applied to just intonation in Western harmony, temperament in Baroque European music, and the intonation of ragas in Hindustani music.
A crucial achievement of recent work has been the import of MusicXML scores in Western music notation, paving the way to using fragments of musical works in BP3’s generative system. The following recordings are entire musical works encoded as single polymetric expressions:
This site includes a documentation of algorithms implemented in Bol Processor as well as tutorials for a better understanding of related concepts in several musical traditions. Basic concepts are exposed to readers unfamiliar with these different cultures.
As an open source project hosted by GitHub, we are taking Bol Processor into the next stage of its evolution. We hope that BP3 will become more modular, separating its computational engines for musical grammars, polymetric expressions, and powerful time-setting algorithms into software libraries that may be incorporated into other open source software.
➡ Contact us!
Bernard Bel & Anthony Kozar
➡ Visit the growing sets of examples and tutorials on this site
➡ Download a PowerPoint slideshow introducing the Bol Processor with sound examples (zip file, 150 Mb)
➡ YouTube video: “Bol Processor - 39 years!”
➡ Join our project on GitHub!
➡ Read the BP3-to-do file