|
Randy,
ita,
John,
If any one is interested I think the paper John is
referring to is:
0314 Pitch
identification of simultaneous diotic and dichotic two-tone
complexes
*
J.G. Beerends; A.J.M. Houtsma
JASA 1989 85(2) 813-819
published while he and Adrianus Houtsma
were at the "Institute for Perception Research" in Eindhoven.
A central processor model was mathematically
described by Julius Goldstein (while he too was at IPR) in:
0066 An
Optimum processor theory for the central formation of the pitch of complex
tones
*
J.L. Goldstein
JASA 1973 54(6) 1496-1516
Fred
------------------------------------------------------
Fred
Herzfeld, MIT class of 1954
78 Glynn Marsh Drive # 59
Brunswick, Ga.
31525
USA
----- Original Message -----
Sent: Tuesday, August 02, 2011 11:49
AM
Subject: Re: correction to post
Dear list,
Periodicity plays a role in pitch perception but is not the
whole story.
In an experiment
performed by Houtsma, many years
ago, one sine goes to one ear and
another, harmonically related sine, to the other, there is no mathematically
periodicity at the fundamental, but melodies can be played using this
missing fundamental showing that a central processor finds the missing
fundamental.
John Beerends
TNO
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
No virus found in this incoming message.
Checked by AVG -
www.avg.com
Version: 9.0.901 / Virus Database: 271.1.1/3805 - Release
Date: 08/02/11 02:34:00
|