extended bridges

Delwin D Fandrich pianobuilders@olynet.com
Thu, 22 Apr 1999 23:30:40 -0700



Eliot Lee wrote:

> At a class taught by del Fandrich, I remember him not advocating extension
> bass bridges, which I don't understand.
>
> After reading W.B. White's book, he writes,"Bridges should not be brought
> too near the edges of the soundboard where elasticity is at a minimum and
> the stiffness at a maximum. In tight places if the string length is to be
> prserved, an extension bridge may save the day."
>
> I wondered what the consensus and knowledgable opinion is from the piano
> builders.  If the extension  bridge is not used what is an alternative?
>
> Thanks,
>
> Eliot Lee

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There was much that was not well understood about piano design when Dr White
wrote those words.  One of those things was the disadvantages of the the bass
bridge cantilever.  For more on this subject look back to the article I wrote
for the Journal on soundboard stresses.

The key phrase here is "if the string length is to be preserved...."  There is
far too much emphasis placed on absolute string length in short pianos.  The
only reasonable way to get a longer string length (i.e., speaking length) is
to make a longer piano.  The problem only arises when the designer tries to
put an excessively long string in a too short piano.  And the only reason for
doing that is to satisfy some poorly conceived marketing story -- there are no
musical benefits.

We regularly make new bass bridges for short pianos that actually shorten the
speaking length of the low bass strings -- particularly the mono-chords -- and
at the same time remove the cantilevers.  The tone quality of the low bass is
always improved.  Besides, if absolutely necessary, it is always possible to
relieve the bass bridge by simply undercutting it a few centimeters.  This
accomplishes the same thing but does not add the excessive mass and the
off-center stress load on the soundboard that are common to the cantilever

Regards,

Del




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