ribs and stuff (was alternatives.)

[Delwin D Fandrich]

Newton Hunt wrote:

> Hi Del,
>
> Then what happens when there is negative crown on one side of the bridge and
> positive crown on the other side.
>
> I have a Knabe 5'4"or so in a church sanctuary now that exhibits this behavior.
> The bridge is actually pulling the stirngs down, not pushing them up.  The edge of
> the bridge closer to the keys is lower than the back edge.
>
> What can be done for this piano short of replacing the board.
>
>                     Newton

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Newton,

This is another subject I wrote about at some length in the Journal.  In fact, it was
one of the first topics I tackled, if I recall.  It was under the Q&A section.  My
Journals are all in boxes or I'd look up the issue for you.  There are a couple of
drawings accompanying the article that might make more sense than my lengthy and wordy
explanation.  If you don't have yours handy let me know and I'll try to track down the
issue.

This problem is often the result of a compression-crowned soundboard going through its
seasonal changes.  The panel is expanding, but the bridge is being held down by the
string load.  It has to go somewhere so it goes up.  Or down.  Whichever is the path
of least resistance.  I've seen more of them with the opposite distortion -- the front
of the bridge being higher than the back.

Probably not much can be done about it short of replacing the board.  If the piano has
been this way for a while the soundboard will take on a permanent set in this
configuration.  Even removing the strings will not alter the shape of the board much.
How old is the piano?  If it is fairly new it might just have excessive downbearing
and removing some of that bearing may improve things.  How does the piano sound?
Specifically, how is the power to sustain balance?  Is the tone percussive or does it
have a fairly uniform decay rate?

Del