Techniques for Polytemporal Composition

Digital computers offer unprecedented flexibility and accuracy for the composition and performance of polytemporal music involving multiple time streams: polyrhythms, metric modulations, multiple tempi, and precisely calculated independent continuous tempo changes (accelerandi and de-celerandi). This article addresses some important musical and technical issues encountered in music with multiple simultaneous tempi, including music with independently fluctuating tempi. The article includes a brief summary of some important precedents in pre-computerized music, a look at some implementations of polytemporality in computer music, and some suggested techniques for designing and manipulating multiple time streams in computer music composition.