Audiogram defects (was Re: Cochlea -- quality of filtering)

BJPARKER bjparker at aol.com
Sun Sep 24 11:45:18 EST 1995


Susan wrote: 
actually, that's not quite true.  one of the beauties of the critical band
theory is that it *does* address the shape and size of the filters.
fletcher, in his original theory, assumed they were symmetrical, but did
not
know for sure.  when patterson and moore created psychophysical tuning
curves they were asymmetrical, so patterson controlled for off-freq
listening by using notched noise.  when he did that, it forced the
subjects
to listen to the filter centered on fs and the bands were shown to be
symmetrical.

- Actually, what I said is accurate. However, the response suggests the
literature I made reference to may not well known or how it shows CB
theory has a weakness.  The work I made reference to agrees with the
Fletcher and Patterson work in that there is a mechanism (yes, probably
peripheral) that aids in the selectivity of the auditory system.  What the
data also shows, however, is that the auditory system processes
information OUTSIDE the "critical band" and it affects the perception of
the signals INSIDE the critical band.  That is, a signal that has exceeded
the critical band can continue to affect perception of a singal within the
critical band.  





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