Lack of low frequency response

[pianoguru at cox.net]

---- Richard Brekne <ricb at pianostemmer.no> wrote: 
> I'm wondering if a nasal sound... with little or no apparent low end 
> response can have to do with LACKof stiffness in the fat part of the 
> soundboard... i.e. in that section that is somewhat front of the long 
> bridge and bass bridge.... low tenor area. I know this seems to go 
> contrary to the usual conclusions we'd jump at.... but it connects with 
> aging soundboards and why they start sounding thin and nasal...

I can't find the exact posting, but earlier in the thread it was suggested that the soundboard might divide into many small "tweeters" and thereby inhibit the full vibration of the soundboard, as a "woofer."  Forgive me if my memory has misconstrued the intent of the statement.  I have seen studies of soundboard vibration where black glitter is sprinkle over the entire surface of the soundboard.  As different frequencies are introduced at different locations along the bridge, the glitter moves to define nodal lines on the surface of the board.  The patterns came out differently for different frequencies.  It seems to me that these nodal divisions of the board do not inhibit the fundamental frequency, but work concurrently with it, in much the same way as a sounding string has a complex envelop of multiple partials at multiple frequency.

Regarding reduction of stiffness in the bass region of the board, I believe you can go too far in that direction.  I am reminded of a piano that makes much ado about its reverse crown and floating soundboard in the bass.  To me it sounds much like an old upright where the bass bridge has come unglued from the apron.

Frank Emerson