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Re: Rationale for Critical Bands


Just to add more confusion, I was wondering about the phase response of the auditory filters. I've always considered that a bandwidth was related to the magnitude response, so critical bandwidth would be oblivious of any phase curvature within a filter, while "auditory filters" would (should) include this phase response.

I realize now that I may have been wrong as the phase response likely originates in the cochlea, isn't it?


PS: glad to see the cochlear modellers back on the auditory list ;-)

On 15/06/2010 02:45, Richard F. Lyon wrote:
Dan, the situation is indeed complicated, but I don't think there's much actual disagreement.

I don't think you'll find any serious scientists placing "the burdon of explaining auditory perception almost entirely upon the cochlea" even though it is as you say "the most-studied and well-understood component of the auditory system." There's an awful lot about hearing that can only be explained in terms of several subsequent levels of processing, and much that can't yet really be explained at all.

For simple phenomena related to the critical band, however, understanding the form of the cochlear filter seems to be enough, or almost enough. The question of whether an auditory filter model can fit both the psychophysical data as well as the biomechanical/neurophysiological data has often been openly discussed; it is not a totally settled question, nor an ignored question. The result so far seems to be that a good fit in one domain can be at least plausible in the other.

In my own recent work, I've been promoting a form of cochlear model that seems to do well on both; that is, it gives excellent fits to masking data, with few parameters (about like gammachirp or a little better), and also has structural relations to the underlying traveling-wave mechanics. Unfortunately, I don't have any journal articles on it; but I can send you some stuff from a workshop talk and recent conference talks if you're interested.


At 9:07 AM +0800 6/15/10, Daniel Bowling wrote:
Thanks to all who responded.

In addition to the public posts I have received several private ones and I think it is safe to say that there is a good deal of disagreement regrading this matter.

My concern is that research has placed the burdon of explaining auditory perception almost entirely upon the cochlea, the most-studied and well-understood component of the auditory system.

Whether the idea is 'critical bands' or 'auditory filters', the bottom line seems to be the same: the results of the psychoacoustic experiments are explained by the physical interaction of vibrations of the BM. This is the claim I am wondering if there is direct evidence for.

Although cochlear models are of great interest, it is not clear to me how demonstrating that roex (or gammachirp) functions are capable of approximating BM motion data explains the perceptual phenomena in question. It is likely that I have failed to come to grips with the implications of these models. However, if cochlear models do hold the key to understanding why we hear what we do, I would greatly appreciate a presentation of the basic argument in simple enough terms to inspire a student to expend the considerable time and energy required to master an understanding of them.


Etienne Gaudrain, PhD
MRC Cognition and Brain Sciences Unit
15 Chaucer Road
Cambridge, CB2 7EF
Phone: +44 1223 355 294
Fax (unit): +44 1223 359 062