Future Prospects

So, we have made pretty good use of the properties of the inner-ear in our spectral models. For example, the peak-dominance of audio perception matches well with the ``unreasonably effective'' sinusoidal model. Similarly, we can inaudibly eliminate 90% of the information in a typical sound, on average, due to auditory masking (which is of course due to peak-dominance as well).

An interesting observation from the field of neuroscience is the following [79]:

``... most neurons in the primary auditory cortex A1 are silent most of the time ...''

This tantalizing observation indicates that there exists some kind of sparse high-level model for sound in the brain. What is the right ``psychospectral model'' for sound? We know that the cochlea of the inner ear is a kind of real-time spectrum analyzer. The question becomes how is the ``ear's spectrogram'' processed and represented at higher levels of audition, and how do we devise efficient algorithms for achieving comparable results?

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About the Author: Julius Orion Smith III
Julius Smith's background is in electrical engineering (BS Rice 1975, PhD Stanford 1983). He is presently Professor of Music and Associate Professor (by courtesy) of Electrical Engineering at Stanford's Center for Computer Research in Music and Acoustics (CCRMA), teaching courses and pursuing research related to signal processing applied to music and audio systems. See http://ccrma.stanford.edu/~jos/ for details.