TitleTimbral Migration: Stochastic Processes for the Control of Smooth Spectral Tranformation
Publication TypeConference Paper
Year of Publication2009
AuthorsMacCallum, J, Schmeder, A, Wessel, D
Conference NameICMC

We present an additive synthesis engine that can produce smooth transitions between timbres without glissandi or audible transients. With this algorithm, one can explore the musically rich area of hybrid timbres that arise as one timbre ``migrates'' into another. This method operates in real-time using live or pre-recorded sinusoidal analyses as input. Parameterization of the migration behavior enables interactive control. We present the history of this engine, which originates from work by David Wessel at IRCAM in the 1970s. We discuss two implementations: a statistical method based on sampling from a discrete probability mass function derived from a sparse input spectrum, and a stochastic local-update method using parallel Markov Chain Monte Carlo (MCMC) processes, which enables control over spectral flux, spectral smearing and migration rate. We conclude with a summary of notable musical uses in contemporary electroacoustic music.