Orthotropic Soundboard (was Laminated Soundboard Ribs)

[Ron Nossaman]

>Perhaps these functions are the primary ones and carrying waves, damping, etc.
>are secondary or insignificant to the soundboard's function.

Secondary, though not entirely insignificant, and cutoff bars are pretty
handy for minimizing unwanted vibrational modes.


>Another aspect of this is that some people seem to feel that there is
something
>magical about the board having orthotropic properties and that wood is the
>choice for musical instrument boards partly because it is orthotropic.  I'm
>unconvinced about this.  I think a soundboard needs to have high stiffness to
>density and some level of internal damping.  When pianos were developed the
>only material available with these properties was wood (softwood).  Now it
just
>so happens that this material is orthotropic.  Some people have concluded that
>this means that the soundboard needs to be orthotropic.  Perhaps they're right
>but I'm unconvinced.  I've seen pianos with laminated boards (which I've taken
>to be essentially isotropic) that seem to serve the same function (whether
they
>do it as well as an orthotropic board is still an open question).  Ron 
>Overs's piano
>which he displayed in Reno is an example.  I don't know enough about the way
>the board is constructed to know if it is truly isotropic.  Perhaps Ron can 
>comment
>on that.
>
>Phil F

I'm one of the other Rons, but I'd like to make an observation here if I
may. The very fact that a large long stiff heavy bridge is attached to the
panel (usually roughly parallel to the grain in a traditional solid panel)
pretty well insures that the assembly won't be truly isotropic, whatever
else is done to it. 
Ron N