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.
Regards,
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
www.thenedra.com