An audio signal (172) representative of an acoustic signal is provided to
an auditory model (105). The auditory model (105) produces a
high-dimensional feature set based on physiological responses, as
simulated by the auditory model (105), to the acoustic signal. A
multidimensional analyzer (106) orthogonalizes and truncates the feature
set based on contributions by components of the orthogonal set to a
cortical representation of the acoustic signal. The truncated feature set
is then provided to classifier (108), where a predetermined sound is
discriminated from the acoustic signal.