Soundboards: Thickness and Area

[Cy Shuster]

Certainly it's typical to make Chladni patterns by applying a series of
vibrations, such as with a violin bow, or mechanical inputs of a certain
frequency.   But I think you have to admit that hitting the board even a
single time is just a subset of the case where you hit it 440 times a
second, isn't it?  A single hammer blow to a string still makes it
vibrate...  The analysis of the board's response to a single blow should
just be one case of its response to multiple blows.

What I was really trying to learn (as I'm still learning) is what
Steingraeber was trying to accomplish by using the sand on an installed
soundboard, and hitting the bridge with a hammer (why not hit some keys, for
example, on a completed piano?).  You said they were looking for where a
line of sand accumulated near the board's edges.  Why?

My point of raising the Chladni patterns is that it seems you could make all
kinds of different patterns appear in the sand, depending on where you hit
the bridge and how hard.  So they must have a certain way they do things,
which gives them repeatable results.

This is another one of our ongoing cases of trying to take well-established
field methods, and look at the theory behind it to see if we can figure out
why it works...

Thanks,

--Cy Shuster--
Rochester, MN