This paper describes an interactive music system that improvises with
a saxophonist, developed in collaboration with John Butcher. In
non-idiomatic group improvisation, musicians make performance decisions
based on well-defined musical parameters such as pitch, as well as
instrument timbre or tone color. For many saxophonists, timbral
variation is a critical structural element.
Our system is able to analyze and "understand" aspects of a human
improviser's performance. Perceptually important features, such as
multiphonics and auditory roughness, are detected in real-time. This
information is used to influence how the system generates response
material. The system is also able to capture timbral variations or
contours over a gesture, and reference these contours when responding
to the saxophonist. Some clips can be found at
http://userwww.sfsu.edu/~whsu/Timbre.
