[CAUT] CAUT Digest, Vol 6, Issue 127

[Richard Adkins]

If I may(I hope you don't mind).... Del Fandrich posted this in 2002 to pianotech:
 
Soundboard impedance is established by three primary characteristics of
the
>soundboard assembly; its mass, its springiness, and its internal
resistance.
>With most of the pianos exhibiting 'killer-octave' problems the problem
lies
>with the reduction of springiness that has taken place in the soundboard>assembly relative to the time when the soundboard assembly was new. Or at>least when it was functioning properly. There is nothing you can do about
>the systems internal resistance and there is not a lot you can do about
the
>loss of springiness except add auxiliary springs to the system, but this
is
>a technology that few have yet to embrace so little is known about the
>procedure or its long term results.
>
>The other thing you can do is add some mass by means of brass (at least
that
>is what I've used) weights attached to the underside of the soundboard
along
>the bridge line. These are installed by drilling through the brass weight
>(start with something in the neighborhood of 75 to 100 grams) and screwing>it to the bottom of the board. The screw should extend well into the
bridge
>body. Put one in the area of shortest sustain and see what happens. You
will
>have to experiment with various amounts of mass to find the amount that
>gives you the best results. Once you've settled on a certain amount of
mass,
>put a bit of PVC-E adhesive between it and the soundboard (to keep it from
>buzzing) and tighten the screw thoroughly. Several weights in the 75 to
100
>gram range spread between the various ribs are better than one two to
three
>hundred gram weight stuck in just one place.
>
>This is not the same as a new and functional soundboard, but it is a lot
>cheaper. If you don't like the results you get from these weights simply
use
>a screw and soundboard button on to cover the hole(s) you've made and
forget
>it. A new soundboard will then be the only solution.
>
>Del
>

Unfortunately, many of us do not have the budget to have new soundboards installed
(let alone a Nossaman re-do)....so we have to make the best of it. Thanks to Del for
sharing this info.
 
Richard Adkins
Coe College
 
 

 
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