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Re: High frequency hearing

One reason for the paucity of data on high frequency hearing
may be the difficulty of obtaining reliable and meaningful values.
As the frequency gets higher, it's harder and harder to find a
transducer with a flat response, and even if you do, the overall
system response may be far from flat due to standing waves
in the ear canal, etc.  In anesthetized animals, you can place
a small probe tube very near the typanum to measure the
actual sound delivered, but at high frequencies even a slight
position change may lead to big differences.  This approach
would have obvious limitations when applied to awake children.

Free-field is of course worse for standing waves, but I suppose
you might ask the subject to move around if the sound is not
at first detectable.  Then maybe you could calibrate (sort of)
by scanning your probe for the peak response in that general
region, and hope it's the same peak the subject found.  Just
a thought.

Robert Masta

         D A Q A R T A
Data AcQuisition And Real-Time Analysis
 Shareware from Interstellar Research