The author discusses three compositions: Déplacements (1979) for guitar and tape, Light (1979) for 14 instrumentalists and two four-track computer-generated tapes and Soft Morning, City! (1980) for soprano, double bass and tape. He discusses his musical language and the structure of these pieces to explain the role of the computer in his creative process. He uses the computer to create two completely different worlds: one of abstract electronic sound and another of synthetic instruments.