[Re: Time to kill the 20KHz myth.]

[Harry Bissell]

Tony:
Depending on whether that was a newer or older unit, you might be surprised
how that 40 KHz was produced. An old RCA "Space Command" sending unit had
spring loaded "hammers" which struck resonant steel bars. Hold THAT to your
ear and you WILL hear it. If the 40KHz is loud enough, non-linear ear response
could allow you to feel the pressure.

I don't agree about the 18-19K. As a child, I told my father (working on a
phono preamp) that I could hear the sine wave oscillator. He said (lovingly)
"BULLSHIT KID... Nobody can hear that high." Mamma said "If my kid says he can
hear it, he can hear it..." Papa said "OK, Turn around, kid..." and started to
sweep down from 30KHz. I could tell him when he got to 22KHz every time,
without looking.

Alas, a couple of years ago (at 40) I repeated the test. Try as I might, I can
only hear up to 18KHz now, and only if I try really hard.

Youth is wasted on the young....  :-) Harry

"Tony Allgood" <oakley at techrepairs.freeserve.co.uk> wrote:
>>22k bandwidth is also a bit of a myth. Listening test have not
>shown that the ear has ANY ability to perceive frequencies over
18-19kHz
>under the best conditions.


I used to have one of those 40KHz remote controls for my telly. If you
stuck it near your ear, as you do, and pressed the button, you would
FEEL it, but somehow not hear it.

Regards,

Tony Allgood, Cumbria, UK

Rack mounted moog filter and the TB3030 SuperBassline projects:

http://aupe.phys.andrews.edu/diy_archive/schematics/oakley/





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