Crown without soundboards

[Ron Nossaman]

Hi Jim,

Even with cracks, the soundboard panel is still doing pretty much the same
thing it always did everywhere except where the cracks are. If the panel
were pushing against the rim to maintain crown, there couldn't be both open
cracks, and crown in the board. The crown is being maintained from millions
of discrete points, to varying degree, everywhere the soundboard panel and
ribs meet and the glue joint is still sound. Gaping cracks totaling 1% of
the total panel area will have nearly no affect on the crown because the
other 99% is still doing it's job. If there is still crown in the cracked
board, it's because both the ribs and the panel are still doing their job.
As long as the glue joints are tight and the panel wood hasn't been crushed
beyond hope (overall), it will still be a soundboard of sorts.  
  

At 12:21 PM 12/29/97 -0700, you wrote:
>Hi Ed:
>
>When one considers a piano soundboard with many splits and there is
>still downbearing, one might think that indeed the ribs are supporting
>the downward force of the string bearing. However, when one also
>considers the fact that as humidity increases, the soundboard rises and
>increases the tension on the strings, one might think that the board is
>the crown supporting member. It is well known that the ribs do not
>lengthen any to speak of when the humidity increases, but the soundboard
>certainly does swell and rise with humidity increases. Perhaps we can
>gain a little more insight from the harpsichord builders who have to
>work with much fewer ribs and funny wavey things that go on with the
>soundboards.
>
>Jim Coleman, Sr.
>


 Ron Nossaman