Toby Rider wrote:
"I been thinking about soundposts and fiddles...Here is how a fiddle works: The top only vibrates at high frequencies. The back only at low. They do not work as a unit, ever. The purpose of the soundpost is to transfer the low frequencies from the bridge to the back. That's why the soundpost is opposite the low strings -- The bridge works like a lever. Since the strings are further from the post, more energy is transferred.
How come it keeps an archtop from feeding back then? It
prevents the top from vibrating on its own - with a
soundpost, ya gotta move the top and the back to get
it going... Well, that's a bit weak, but the best I
could do."
Toby
As to the guitar -- I don't know guitar acoustics, but what he said makes sense. Durring feedback, the top of the guitar is probably vibrating freely, and a dowel trying to tie it to the back would stiffen it. Two might be even better. On a violin, part of the purpose of the f holes is to make a portion of the top move more freely (more top end).
If he is only playing it because of it's looks (i.e. he never uses it acoustically). He could stuff it with bits of foam or something. I would even say you could fill it with expanding foam, but I won't say that (because you could probably rip the instrument apart, if you weren't familiar with the foam!)
Bob
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