Pitch and timbre manipulations using cortical representation of sound

The sound received at the ears is processed by humans using signal processing that separates the signal along intensity, pitch and timbre dimensions. Conventional Fourier-based signal processing, while endowed with fast algorithms, is unable to represent a signal easily along the lines of these attributes. We use a recently proposed cortical representation (Elhilali, M. et al., Speech Communications, 2002) to represent and manipulate sound. We briefly overview algorithms for obtaining, manipulating and inverting cortical representation of a sound and describe algorithms for manipulating signal pitch and timbre separately. The algorithms are first used to create the sound of an instrument between a "guitar" and a "trumpet". Applications to creating maximally separable sounds in auditory user interfaces are discussed.