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Re: Traveling waves or resonance?
May I ask you and Martin for not neglecting our common insight that it's overdue
to finally bury all theories which assume essential transmission of energy within
basilar membrane from base to apex the main principle of hearing? This includes
the hydromechanical model by Lighthill alias Lichtenberg as well as all
transmission line models.
Let's deal with the objection: 'Resonances are generally way too narrow (too
sharp and too symmetrical compared to real data or to TW models'. Maybe such
objections are justified if we have a too simple idea of local resonance. I am
unhappy with the alternative decision between traveling waves or resonance, for
First of all, a traveling wave phenomenon is observable. It even includes wave
propagation inside a finally standing envelope. However, the phenomenon is not
really based on lateral wave propagation. For a comparison, look into pertaining
http://iesk.et.uni-magdeburg.de/~blumsche/M275 and M277.
Notice, what I named 'the natural spectrogram' is distinguished by not relying
an any parameter except for attenuation. Nonetheless, it well agrees with
shamelessly tweaked models. In M277 I try to explain how coarse cochlear
frequency analysis can be an advantage: Perhaps, cochlear frequency analysis is
just the first step of an overall autocorrelation. The second (cepstral-like)
step of this joint analysis requires enough bandwidth in order to form an
auditory image as a spectrally-based time pattern.
It is my speculation that such iterative use of simple principles was a starting
point for evolution of mammal intelligence. Martin reminded of the older
biochemical, i.e. electrical, sensors being subject to tight frequency
restrictions. Mammals got superior with their faster mechano-electrical
mechanism of preamplification by means of outer hair cells.