Decomposing Autumn: A Component-Wise Recomposition

The vast musical possibilities of decomposing acoustic spectra, and their re-combination/resynthesis, has yet to be deeply explored as a compositional device. In this piece, we present a component-wise decomposition of Autumn in Warsaw, the sixth in Gyorgy Ligeti’s 2 book of piano etudes, coupled with real-time componentwise audio retrieval, as a foundation for a structured improvisation on the same. Shiftinvariant Probabilistic Latent Component Analysis (PLCA) is employed as a decomposition technique to obtain a corpus of separated sound fragments, which is then queried by a live improviser. This approach effectively bridges the fields of independent/nonnegative/latent component analysis and composition, and constitutes an attempt both to deepen the exploration of possibilities in decomposition as a methodology for composition, as well as an attempt to catalyze Bernard Stiegler’s ‘new objectification of sound’.