compression waves

John Delacour JD@Pianomaker.co.uk
Thu, 22 Nov 2001 00:30:59 +0000


At 11:48 PM +0100 11/21/01, Richard Brekne wrote:
>Might I point out to you two that the fact that the frequencies of the LM are
>effected by the speaking length in no way necessarilly bears on whether or not
>those frequencies can run along the whole of the string unneffected by
>boundries ?
>
>This is also born out by the rod experiment that I posted a link to the other
>day. The frequencies of the LM is determined by where the clamp on the rod is
>placed, but that in no way affects either the presence or the 
>strength of those
>frequencies on the other side of that clamp.

I saw the movie and I'd say that rod was at least 10mm thick and the 
clamp not very massive.  I'm not sure these two things are anomalous. 
Between the terminating properties of the fiddle bridge on the one 
hand and the upright agraffe, soundboard bridge etc on the other, 
there is a transitional region.  For example, the double angle of the 
upright agraffe is sufficient to act as a terminal, whereas a single 
15° bend might not be, or might slightly lower the base frequency. 
Conklin touches on this in his patent -- one of several areas where 
empiricism interferes with the application of his method.


>I am also building a monochord to see if I can show exactly this behavior.

We must all get together and give a concert!  If you happen to have a 
stainless steel kitchen sink with a draining board, stand it over 
that and notice the difference.

JD





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