Soundboard Sound Tranmission

Richard Brekne Richard.Brekne@grieg.uib.no
Fri, 25 Oct 2002 22:44:19 +0200


Farrell wrote:

> Here is another question. I hear so much about sound traveling along a bridge, along ribs, through soundboards, bouncing off rims, zinging here and there. Does sound generated by the vibrating string actually travel along all/some of these routes, or is it a more simple process of the string vibrates, which in turn makes the bridge vibrate, which in turn makes the board vibrate, with in turn makes the air vibrate which our ears/brain detect as sound?
>
> Terry Farrell
>

Grin... oh good lord... here we go again. Dont you remember all the fun we had just before last Christmas and into the new year.

My take is that for the most part we are dealing with Transverse vibrations that are in reality quite a bit more complicated then simple 2 dimensional plate vibration theory accounts for. There is some recent science that points to more complexity, and there are plenty enough acousticians to talk of bending waves, or about longitudinal componets contributing to the transverse waves developing in the panel.... but when all is said and done... the panel
has to have a very large transverse vibrational componet, as this is the only thing thats going to get the air moving.

So... sure ... hit the string and vibrations of both transverse, longitudinal, and probably more complex wave types are going to bounce all over the place.... you can feel them on your tuning hammer, on your knee under the keybed (I actually know a fellow who tunes the bass this way).  Probably, its all very very much more complicated then any of us know, and perhaps thats one of the reasons a truly complete mathmatical model does not exist. But for our
purposes..., I am not so sure how complicated we need to make it.

So .... why do you ask ? :)

--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html



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