Soundboard stiffness variances

[David Love]

The piano world is replete with living (and dead) examples of the
unpredictability of the compression crowning method.  Anyone who has paid
attention has heard the evidence.  NY Steinway pianos are a great source for
this study especially if you take the "different personalities" euphemism as
a statement to the effect that each piece of wood will respond differently
to their own particular method.  This is not to be read as a criticism of
their choice, necessarily.  It is their choice and there are examples where
it's produced a very musical outcome.  

While variations in rib strength do occur they can be easily tested prior to
gluing them up as some rebuilders do.  The purpose of the laminated rib is
also to create a more uniform MOE from rib to rib by mixing lots.  

I don't want to discourage anyone, though.  I will be on the sidelines
cheering anyone who wants to embark on a scientific study to prove the true
limited variability of the compression of spruce in the compression crowning
method.  You will need a skilled grant writer though as the costs will be
high, too high for me and, unfortunately, I'm not in a position to donate
any money to the cause--at least not until the kids are out of college. 

David Love
davidlovepianos at comcast.net 
www.davidlovepianos.com

...
As far as the claim that the degree of unpredictability being 
proportional to the degree with which the assembly is reliant on 
compression.... where is the study that supports this ? Proportional has 
very a specific meaning when used thus. Strikes me right off that given 
the fact that the rib is just as likely to show wide variability in its 
strength properties... particularly bending strengths... such a claim is 
taken out of thin air. JMMV