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Re: correction to post

Dear list,

Isn't the 'missing fundamental' phenomenon is easily explained by the fact that the auditory system recognizes periodicity (it is known that the auditory system preforms a time-domain analysis in addition to freq-domain analysis), and the periodicity is 'mathematically' there (i.e, no illusion whatsoever)?

The periodicity is determined by the least-common-multiple of the periodicities of the present harmonics, so if (for example) a sound is composed of sines of frequencies 200Hz, 300Hz, and 400Hz, the periods are 5msec, 3 1/3msec, and 2.5msec, so the least-common-multiple is 10msec (2 periods of 5msec, 3 periods of 3.33msec, and 4 periods of 2.5msec), which is of course the periodicity of the sum of the sines, or in other words 100Hz. (actually it is the same as the greatest-common-divisor of the frequencies).

Itamar Katz

On Tue, Aug 2, 2011 at 5:13 PM, Ranjit Randhawa <rsran@xxxxxxxxxxx> wrote:
Dear Nedra,
In my opinion the most enduring (over 200 years) of all auditory "illusions" is what has been called the "missing fundamental". The fact that this has not been satisfactorily resolved by the tortured use of existing signal processing techniques leads some, including yours truly, to believe that the auditory system has figured out a unique way to do frequency analysis and to meet the dictum in biology that "form follows function". Taking into account where we are and the discussions that take place, e.g. this forum, it is interesting that there has been no discussion as to why the cochlear has the shape it does. Therefore some experimental phenomenon that we may call as an illusion, could have a very natural consequence of how frequency analysis is done. One is lead to believe that we are truly very far from understanding how the auditory system works and therefore hearing aid designs are a bit of a hoax foisted on the "proletariat".  Sorry if I sound a bit harsh, but I think it is time people recognized that the emperor has not clothes.
Randy Randhawa

On 7/30/2011 3:16 AM, Nedra Floyd-Pautler, LLC wrote:
My apologies for an over-active spell checker that changed "people" to "proletariat" in my recent posting. Below is the message I intended to send:

I'm a science writer/audiologist researching an article on auditory illusions. What value do they have "on the ground" for people with hearing deficits? Do what they tells us about the brain and hearing have application to hearing aid design? 

Thank you,
Nedra Floyd-Pautler