Sound waves(The behavior of soundboards)

[Ron Nossaman]

>    If the sound is the same on both sides of a piece of 1x1 maple
>outside of the piano however long it then follows that the soundboard has
>a great deal to do with the difference between top and or side of the
>bridge being struck. 

Yes it does.


>Have you any info about the grain direction of
>either bridge that you tested? I've not seen a recent Steinway with a
>good quarter sawn bridge cap. How much would this effect the differences
>in the sound you hear?

The details of bridge construction won't have much to do with it. The
biggest difference is due to the fact that it's some harder to displace the
bridge parallel to the soundboard panel than perpendicular to it.


>    Secondly can you establish or even theorize that the difference has
>anything to do with the glue joint between cap and bridge? I don't recall
>you saying which part, top or side, sounded better, stronger, clearer. Is
>striking the side thus eliminating or bypassing the glue joint a better
>sound? 

Contrary to incredibly tenacious mythology, glue joints in bridges have
nearly nothing to do with sound production unless they fail. Tapping the
top of the bridge results in a lower pitched louder sound, and tapping the
side, a higher pitched quieter one. The difference is from the stiffness
and resonant frequency of the assembly in the different directions. Given a
construction material, resonant frequency is determined by stiffness and
mass. The higher the stiffness, and the lower the mass, the higher the
resonant frequency. The lower the stiffness and the higher the mass, the
lower the resonant frequency.


>If every glue joint is an impediment to good tone quality then it
>would seem that experiments should be made to eliminate the use of wood
>for soundboards and bridges altogether.

Glue joints aren't an impediment to good tone at all, but it's entirely
reasonable to presume that there could be a better soundboard material than
wood.


> What trade - offs would there
>be to using different materials in the building of these cherished items?

The worst detriment to using different materials would be the entrenched
and thoughtless prejudices of the public and technical community. Piano
performance stands to gain by trying something different. 


>Depending on how radical manufacturers might ever get in production and
>materials differences at what point would the product need to take on a
>different name?

Good question, considering that the Linder, Fazioli, Poole, Steinway,
Grand, Yamaha, Kawai, Walter, Baldwin, Lester, etc, etc... are all called
pianos. The number of legs seems to have some influence on naming conventions. 



>    Forgive the silly musings of a sleep deprived compatriot. It is an
>interesting discussion that you folks are undertaking. I'm enjoying what
>I can grasp of it.
>
>Greg

Not silly at all, but it is bed time.

Ron N