evaluating sdbd. crown & bridge downbearings in a new piano

[Ron Nossaman]

> This whole
>issue should have been -- indeed, has been -- laid to rest years ago.  I
>often wonder if techno/mythology has as strong a hold on technicians in
>other industries/professions as it does in the piano world.  This is all
>fairly basic wood technology.  None of this is really open to speculation or
>to argument.  The basic principles are easily proven if you wish to take the
>time to do so.
>
>Del


I'd like to add something to what Del said here, because I don't recall it's
having come up before, and I'd like to throw it in before the topic goes off
on another tangent. Besides the long term dependability of the RC system,
there is one overwhelming short term, or design benefit... stiffness
control. The stiffness of a CC assembly is almost entirely at the mercy of
the panel thickness and density, and is very difficult to anticipate. The
rib stiffness will have some effect on the final depth of crown and total
weight, but the panel mostly controls the assembly stiffness. In the RC
system, the designer can specify and pretty closely anticipate both the
weight and stiffness of the assembly as a whole, and in different areas of
the assembly, by the rib dimensions. 

 Ron N