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Re: average(?) of spontaneous otoacoustic emissions
Dear Bruno and others,
Interesting question. With the currently most advanced measurement
technique, which has been in use since 1990 (!), the bulk of human
spontaneous otoacoustic emissions (SOAEs) was recorded in the 1-4 kHz range.
Therefore an "average spectrum" does not "make sense".
There is not even one mode, somewhere in this range. In fact, there are two
modes, one at 1.5 kHz and one at 3 kHz, with a sharp dip in the distribution
curve at 2.14 kHz.
The bimodality appeared first in 1993 in Fig. 6, but without being mentioned
in the text, in:
A detailed analysis of the bimodality appeared in 2006:
The data that were recorded by Zwicker's doctoral students Eberhard Schloth
and Christoph Dallmayr in the early and mid-1980s and were later republished
by Zwicker and Fastl in 1990 (not 1999; Zwicker died in 1990) are
unfortunately outdated. Even the best data that we have today, those that
were collected around 1990, still reflect measurement limits.
Yes, SOAEs are perhaps the most thrilling phenomenon in the hearing machine.
David Kemp, who made them to a fact in the late 1970s, should long have been
given a Nobel Prize for his work. The reason why this did not happen is as
simple as sobering. The committee would have been unable to say what he
There is still no generally accepted understanding of how and why SOAEs are
generated. Due to several false beginnings in the field of cochlear
mechanics, as often discussed on this list, many simply applied the first
law of science:
"If we don't understand it, it can't be relevant."
Have a nice day.
Neuroscience of Music
web site: http://www.neuroscience-of-music.se/index.htm
Subject: Re: average(?) of spontaneous otoacoustic emissions
From: "Bruno L. Giordano" <brungio@xxxxxxxx>
Date: Tue, 7 Aug 2012 15:11:05 +0100
Dr. Reinhart Frosch kindly referenced this figure:
Fig. 3.12 of Zwicker and Fastl, Psychoacoustics, Springer, 2nd ed.
(1999), is a two-dimensional representation (SPL versus frequency) of
SOAEs from about 100 normal ears.
On 07/08/2012 1:48 PM, Bruno L. Giordano wrote:
I would like to take a look at the spectrum of spontaneous otoacoustic
emissions averaged across a possibly large number of normal-hearing
Can someone please suggest a reference? Does an average spectrum make
sense when considering the amount of interindividual differences?