Jean-Claude Risset is a French composer and respected pioneer in the field of computer music. Beginning in the mid '60's, Risset worked alongside Max Matthews at Bell Labs. Using Matthews' MUSIC IV software, Risset digitally recreated sounds of brass instruments. He is also credited with undertaking the first experiments in FM synthesis (think Yamaha DX series synthesizers) and waveshaping. Risset is also widely acknowledged for his elaboration on the discreet Shepard scale, an auditory illusion of a tone continually ascending or descending but ultimately never getting higher or lower in pitch. Risset's development, referred to as a Shepard-Risset glissando, has a tone that seems to rise or descend continuously in pitch, yet always return to its starting note. Risset created a similar rhythmic effect using drum samples. Both of these effects can be heard here. A further interesting development occurred in 1986 when psychologist Diana Deutsch reported that when a pair of Shepard tones are played in unison, seperated by an interval of a tritone, the pitch can be perceived as either ascending or descending. This is referred to as the tritone paradox.
Mutations features four compositions. The title track was commissioned in 1969 and composed for magnetic tape and synthesizer in 1970 at Bell Laboratories. "Dialogues" was composed in 1975 for a chamber ensemble of flute, clarinet, piano and percussion. The ensemble is processed on magnetic tape. "Inharmonique" (1977) is a collage for magnetic tape consisting of synthesized tones and sparse soprano singing. "Moments Newtoniens" was comissioned by Radio-France for the 50th anniversary of the death of Isaac Newton. Its written for a chamber ensemble featuring a string quartet, two trombones and one piano processed with magnetic tape.
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