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Re: auditory distortion caused by yawning
Dear Harriet, Martin, Roger, Yi-Wen, and List,
In a recent publication  I have proposed a "sensory-
consonance condition b" (few or no large gaps in the pattern
of partial-tone excitation peaks on the basilar membrane of the
inner ear), to be added to "condition a" (i.e., to the Helmholtz
consonance condition, few or no pairs of partial tones having
nearly equal frequencies and thus generating disagreeable
beats). Violation of my condition b, however, is perceived as
disagreeable in the sense of "hollow", rather than in the sense
of "dissonant" or "discordant". An increase of dissonance
through yawning therefore appears to imply an increasing
violation of the Helmholtz condition, i.e., a level increase of
those pairs of partial-tone excitation peaks which even in
comparatively consonant chords have nearly equal frequencies.
For instance, in the major third consisting of two simultaneous
harmonic complex tones C4 (264 Hz) and E4 (330 HZ), the sixth
partial of the deeper tone has 1584 Hz, and the fifth partial of
the higher tone has 1650 Hz. These two partials generate 66
beats per second, fairly close to the (broad) roughness
maximum, discussed in , at a beat-rate of
(1.1 s^-0.5) * sqrt(1617 s^-1) = 44 s^-1 .
Second example: in the minor third consisting of two
simultaneous harmonic complex tones E4 (330 Hz) and
G4 (396 Hz), the fifth partial of the deeper tone has 1650 Hz,
and the fourth partial of the higher tone has 1584 Hz. These
two partials also generate 66 beats per second, close to the
(broad) roughness maximum at a beat-rate of 44 s^-1.
How can yawning selectively enhance the cochlear
amplification at frequencies of about 1.5 kHz and higher?
Possibly, increased dissonance perceived after yawning is
caused by the active cochlear amplifier (CA) being turned off
before yawning and turned on after. Near 300 Hz, the CA
amplification factor is close to 1.0, whereas in the several-kHz
region, in a healthy cochlea, that factor can be as high as
1000 (i.e., 60 dB).
 R. Frosch, "Psycho-Acoustic Experiments on the Sensory
Consonance of Musical Two-Tones", Canadian Acoustics,
Vol. 35, No. 3 (2007) 38-45.
Dr. phil. nat.,
r. PSI and ETH Zurich,
Phone: 0041 56 441 77 72.
Mobile: 0041 79 754 30 32.
E-mail: reinifrosch@xxxxxxxxxx .
Datum: 17.10.2008 21:24
Betreff: Re: auditory distortion caused by yawning
I wouldn't imagine the hard cochlea being physically altered
with just a yawn. I would think it would have more to do with
change in middle ear pressure and TM mobility...much like we
yawn to open our Eustachian Tubes.
Prof Roger K Moore wrote:
> Dear List,
> I have often noticed that if I yawn while listening to music, I
> experience a noticeable distortion of the auditory
> experience - in particular, the sounds appear to become
> discordant. Is this a well known effect, and can it be easily
> explained as the result of a physical distortion of the
> cochlea? If so, what does it say about timing-based theories
> of timbre perception?
> Best wishes
> Roger K. Moore