Fw: Soundboards: Thickness and Area

[Michael Gamble]

Hello Cy Shuster
There are so many, many variables in the density, close-graininess of wood
etc. that we only have control over how we cut it, treat it, dry it etc.it.
I cannot see how we can apply a rigid scientific approach to this natural
substance. I suppose no two soundbords, however close a tolerance we apply,
will display identical characteristics. They will bend and flex and have a
tonal colouring all of their own. Rather like finger-prints I suppose. Do
you reckon that, having applied the "sand test", they modify the soundboard
by planing and scraping and sanding before reapplying the "sand test"? Then
they varnish it - and it changes all over again. It is said that the quality
of sound produced by a Stradivarius is due to the secret formula of his
varnish!
Kind regards
Michael G (UK)
----- Original Message ----- 
From: "Cy Shuster" <741662027@CHARTER.NET>
To: "Pianotech" <pianotech@ptg.org>
Sent: Tuesday, October 21, 2003 8:29 PM
Subject: Re: Soundboards: Thickness and Area


> 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
>
>
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