Soundboard drydown for installation

[John Delacour]

At 15:56 -0600 22/1/08, Porritt, David wrote:

>...When a sounding board has a compression ridge that is a spot where the
>integrity of the board - as a single piece - has been compromised.

Sure

>   That is also the place that will open up as a crack when low humidity
>arrives.

That's rather less sure in my experience, though I have colleagues 
who claim  have seen compression marks develop into open cracks.  In 
certain makes I expect to find open cracks and a smooth board, in 
others compression marks with no opening up.  I suppose that given 
sufficient aridity the board will lose all internal compression and 
have no more strength to push the slipped rings of the compression 
ridge together, at which point the board will actually crack at this, 
the weakest, point.  Usually, I find, there is enough compression in 
the board each side of the ridge to push it together, but then our 
climate is not that of much of America.

>   However, a direct quote from the new Steinway World-Wide
>Technical Reference Guide:
>
>"...This ridging does not mean that the board is cracked. The opposite is
>true. The board is under tension and functioning as it should..."

And I say, Mr. Steinway Salesman-Apologist, that you should learn 
that tension is precisely the opposite of compression :-)

JD