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Re: average(?) of spontaneous otoacoustic emissions

Dear Martin and others,

1) After having looked at your 2006 bimodality paper (referenced in your post below) I now understand that you were not amused by my recommendation of an older publication on SOAEs.
2) Who discovered SOAEs? In Section 5.2.2 of Patuzzi's Review in "The Cochlea" (Springer, 1996), that honour is attributed to J.P. Wilson (1980) rather than to D.T. Kemp (1978). The two corresponding papers are:

A) D.T. Kemp, "Stimulated acoustic emissions ...", JASA 64 (1978) 1386-1391.

B) J.P. Wilson, "Evidence for a Cochlear Origin ...", Hear. Res. 2 (1980) 233-252.

In Fig. 2 of paper A, there are, in the waveforms E, F, and G, stationary beats (at delays ranging from 15 to 30 ms) which I interpret today as SOAEs triggered by the tone bursts. In his conclusions, however, Kemp mentioned emissions lasting "for some tens of milliseconds after impulsive acoustic excitation", whereas, AFAIK, SOAEs last typically for much longer times.

In Fig. 13 of paper B, Wilson presented "frequency analyses of ear-canal `background noise` corresponding to subjective tinnitus in two subjects". These spectra contained narrow peaks at 1158 and 2610 Hz.

Reinhart Frosch,
Dr. phil. nat.,
CH-5200 Brugg.
reinifrosch@xxxxxxxxxx .

----UrsprÃngliche Nachricht----
Von: nombraun@xxxxxxxxx
Datum: 08.08.2012 14:33
An: <AUDITORY@xxxxxxxxxxxxxxx>
Betreff: 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unfortunately outdated.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.


Martin Braun
Neuroscience of Music
S-66492 VÃrmskog
email: nombraun@xxxxxxxxx
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:
>> Hello,
> I would like to take a look at the spectrum of spontaneous otoacoustic
> emissions averaged across a possibly large number of normal-hearing
> individuals.
> Can someone please suggest a reference? Does an average spectrum make
> sense when considering the amount of interindividual differences?
> Thank you,
>      Bruno