audible resultant from two supersonic frequencies?

[Allan L. Gilreath]

Ric,

I would think that it's certainly possible.  I haven't tried it with
those particular frequencies but the oscillators used in radio work
easily set up sum and difference frequencies that can then be heard when
detected.

The catch in piano work may be the short duration of these high
frequency tones generated by the piano.  If I can get a little time, in
the middle of the other experiments in progress and actual work to be
done, I'll try to check this empirically.

Allan
Allan L. Gilreath, RPT


-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
Behalf Of Richard Moody
Sent: Monday, December 02, 2002 11:25 PM
To: cedel@supernet.com; Pianotech
Subject: Re: audible resultant from two supersonic frequencies?


----- Original Message -----
From: Clyde Hollinger <cedel@supernet.com>
To: Pianotech <pianotech@ptg.org>
Sent: Monday, December 02, 2002 6:06 AM
Subject: Re: audible resultant from two supersonic frequencies?


> Ric,
>
> I am confused by your question.  First, do you really mean
>supersonic,  defined as greater than the speed of sound waves?  I
>think you may mean ultrasound, defined as sound with a frequency
>greater than 20,000 Hz, which is approximately the upper limit of
>human hearing.

Clyde,
    You had me doubting for a second, thanks for the point out.
    I am using the definition as given by Webster's 3rd New
International. "Supersonic 1: having a frequency above the
audibility range of the human ear or greaterh than about 20,000
cycles per second --- used of waves and vibrations; compare
infrasonic, sonic. "
    Yes "supersonic flight" is definition number two.  And yes
then I mean "ultrasound" since I see it is defined as. ":a wave
phenomenon of the same physical nature as sound but with
frequencies above the range of human hearing--- also called
supersound".    There is also "ultrasonics" ":the science of
ultrasonic phenomena : supersonic "


>What
> would be the point of experimenting with sounds we can't hear?

The question is,  are there AUDIBLE resultants, which is a sound
we CAN HEAR, that is produced from two frequencies we can't hear
such as 20,440 - 20,000 hz which gives on paper 440 hz  or A440
which certainly we can hear.   An experiment has to be conducted
to determine if this is true.   I am wondering if this has ever
been done, and if not how might it be done?   I need two audio
frequency generators?   Can the computer give hz over 20,000?
How bout tune lab? Would I need two?     ---rm   (the "r" stands
for 'ric' and the "m" stands for "M")





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