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Ear damage by MP3,DVD and digital TV? (more explanations)

CYBERYOGI =CO= Windler windle_c at informatik.fh-hamburg.de
Mon Dec 9 17:29:42 EST 2002

The compensation circuits are a system of neurones, which filters the internal
interference resonances and the after-roaring (resound) from the basilar
membrane out of the data from the vibration sensors ("hair cells") inside
the cochlea to prevent the consciously perceived signal from getting distorted
by disturbing roaring noises. Also the static noise from the sensor cells is
filtered out here, because otherwise it would turn into a continuous audible

The problem is the method by that the internal calibration of the hearing
functions neurologically. The cochlea and its compensation circuits form a
very complex cybernetic system, in which not only disturbing signals are
filtered out afterward, but instead the compensation circuits in the brain
continuously send compensation signals through additional nerve lines back to
the cochlea to change the fluid pressure in the sensor cells ("hair cells")
and this way control their sensitivities (operating point) separately for
the individual frequencies. (The construction of the sensor cells resembles
rather liquid filled long balloons and has in fact no similarity with
"hairs".) This way maladjustments of the compensation circuits have a direct
influence on the operativeness of the cochlea itself and thus can disturb the
perceptibility of sounds already at the very beginning of the signal
processing chain.

A maladjustment here could possibly even destroy the sensor cells itself by
overload, so far the compensation circuits successlessly attempt to drive the
operating point of particular sensor sells higher and higher when they don't
receive from these the expected signal pattern for a certain sound (e.g.
because the expected spectral signal component was removed by data reduction).

Whether such destructions indeed can happen by data reduction is unknown, but
all nerve cells generally react extremely delicate on overload by continuous
high intensity signals, because in the cells the repair mechanisms those are
crucial for their survival run out of energy by this. And such a fatal signal
could theoretically also be generated by the compensation circuits when due to
data reduction they fail to detect an expected spectral sound component and
therefore attempt to increase the operating point of the affected sensor cells
until they finally produce a (continuous) static signal. (I don't claim here
that this destruction unavoidably happens, but by the functionality of the
human hearing this would be quite comprehensible.)

To survive overloads, overloaded neurons tend to reduce their own sensitivity
by removing many of their neuro-transmitter receptors as an emergency measure.
When this happens with the sensor cells of the cochlea, the result would be an
at least temporary worsened aural acuity. Since hearing problems with young
people become more and more widespread, and datareduced audio already nowadays
is used for many radio and TV broadcasts, it is strictly necessary to do more
neuroacoustic research before defining the CODEC standards for replacing the
analogue radio and TV systems with digital ones.

                         MAY THE SOFTWARE BE WITH YOU!

I                  CYBERYOGI Christian Oliver(=CO=) Windler                  I
I         (teachmaster of LOGOLOGIE - the first cyberage-religion!)          I
I                                      !                                     I

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