Re: audio feedback

[brian whatcott <inet@INTELLISYS.NET>]

Lois,
It's an interesting question: if wetware designs rely on electrochemical
signalling specified at 120mV resting, with ground going pulses of say
1 ms duration repeating at a variable rate of a few hundred Hertz, and
propagating at less than 100 m/s., how on Earth do they handle signal
discrimination of audio signals with a spectral range of interest up
to 16000 Hz?

They do it like machines discriminate the spectral content of light:
 by spreading the components out physically into a rainbow in the
spectrometer.

 The audio analog is the organ of Corti which (so the place theory goes)
specifies particular hair cell locations to transduce particular audio
frequencies in the inner ear.

 It happens that an electrode introduced into this space can sense an
integrated version of the various nerve signals - so that
a passable analog electrical audio signal is available there,
the 'cochlear microphonic'.

 The organ is sensitive - but it was unexpected that a particular
nerve if firing unbidden could not only stimulate the subjective
sensing of a continuous tone, but apparently can (in particular
cases) generate a detectable sound via the same arrangement,
working backwards, so to speak.

 This is about as expected to physiologists, as would be noting
 that people complaining of starbursts of light when they rub
their eyes, can actually produce light flashes in a dark room.
(This is purely hypothetical as far as I know.
But you could try it?  :-)

Brian


At 08:34 10/13/99 -0400, Lois Breur Krause wrote:
> OK, I have constant, and rather annoying, tinnitus. Does anyone know what's
> causing it?  I have this idea if knew what was causing it I might have a
> clue how to make it stop!  So here I am if anyone has the equipment and
> wants to try to pick it up.
>
>
> > Unlikely experimental suggestion follows:
> > 'Tinnitus' is a perceived sound or noise in the ears. It can be very
> > distracting and be a precursor to deafness.
> > It has been reported that subjects with a well-defined tinnitus tone
> > can share the sound, if a sensitive microphone is placed in their outer
> > ear.
> >
> > i.e there is the possibility of a two way transduction of sound.
> >
> >
> > brian whatcott
>
> Dr. Lois Breur Krause
brian whatcott <inet@intellisys.net>
Altus OK