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Re: High frequency hearing
I don't know if this is the paper that Lars refers to, but I am curious
to have the auditory list's opinion on this topic. It's not clear to me
whether the effects reported could be some artifact or if they're real.
You can find the entire paper on-line, but here's the reference and the
abstract. Any thoughts?
Oohashi, Tsutomu, Emi Nishina, Manabu Honda, Yoshiharu Yonekura,
Yoshitaka Fuwamoto, Norie Kawai, Tadao Maekawa, Satoshi Nakamura, Hidenao
Fukuyama, and Hiroshi Shibasaki.
Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect.
J. Neurophysiol. 83: 3548-3558, 2000.
Although it is generally accepted that humans cannot perceive sounds in
the frequency range above 20 kHz, the question
of whether the
existence of such "inaudible" high-frequency
components may affect
the acoustic perception of audible sounds remains
unanswered. In this
study, we used noninvasive physiological
measurements of brain
responses to provide evidence that sounds
high-frequency components (HFCs) above the
audible range significantly
affect the brain activity of listeners. We used
of Bali, which is extremely rich in HFCs with a
structure, as a natural sound source, dividing
it into two components:
an audible low-frequency component (LFC) below
22 kHz and an HFC
above 22 kHz. Brain electrical activity and
blood flow (rCBF) were measured as markers of
while subjects were exposed to sounds with
of LFCs and HFCs. None of the subjects
recognized the HFC as sound
when it was presented alone. Nevertheless, the
power spectra of the
alpha frequency range of the spontaneous
(alpha-EEG) recorded from the occipital region
statistical significance when the subjects were
exposed to sound
containing both an HFC and an LFC, compared
with an otherwise
identical sound from which the HFC was removed
(i.e., LFC alone). In
contrast, compared with the baseline, no enhancement of
alpha-EEG was evident
when either an HFC or an LFC was presented
emission tomography measurements revealed that,
when an HFC and an LFC
were presented together, the rCBF in the brain
stem and the left thalamus increased
significantly compared with
a sound lacking the HFC above 22 kHz but that
was otherwise identical.
Simultaneous EEG measurements showed that the
power of occipital
alpha-EEGs correlated significantly with the
rCBF in the left
thalamus. Psychological evaluation indicated
that the subjects felt
the sound containing an HFC to be more pleasant than
the same sound lacking
an HFC. These results suggest the existence
of a previously unrecognized response to
complex sound containing
particular types of high frequencies above the
audible range. We term
this phenomenon the "hypersonic
At 16:04 07/11/02 +0100, you wrote:
And yet we now have audio equipment with 96
kHz sampling - what a waste!
The only evidence I have seen - which as been forwarded by the '96
proponents and audio manufacturers are some EEG measurements done on
exposed to ultrasound, using few subjects. It is a rather indirect
and I don't know if this has been published.
The results could be interesting, and like Bob points out the only
meaningful way would be to have the object move. This could be done
some kind of moving chair that would circle a small region within
duration of one stimulus.
DK - 2900 Hellerup
phone: +45 39 13 85 42
fax: +45 39 27 79 00
From: David Robinson
Sent: 5. november 2002 15:28
Subject: High frequency hearing
I am trying to discover the limits of high frequency
hearing in the most sensitive human listeners.
The standard MAF curve(s) are of little use because
a) The data does not extend to very high frequencies
(i.e. it usually stops between 15 and 20 kHz), and
b) the data is based on median results.
Ideally, I would like real data to confirm the
anecdotal evidence that young and/or gifted listeners
can hear up to 25kHz (or beyond?). Equal loudness data
would be useful too, but the most useful information
would be an indication (very very roughly) of the % of
listeners of a particular age who can hear a particular
frequency at a particular amplitude.
Is there anything like this in the published
literature? I have looked several times, but everything
I find stops at 16kHz! Also, anything other than median
results seems very thin on the ground.
Thanks in anticipation of any help - any pointers would
be very greatfully received!
P.S. I can't see the local primary school being too
keen to lend out children for a high frequency
listening test - is this the reason no one else has
Please use new e-mail address from now on:
Robert J. Zatorre, Ph.D.
Montreal Neurological Institute
3801 University St.
Montreal, QC Canada H3A 2B4