S&S capo

[Mark Bolsius]

Ron makes a good point here, I saw a rebuild in a concert  Grotrian Steinweg
done in Sydney Australia by Ron Overs, where the front duplex was too long
and produced a frequency low enough to be a real problem. His fix involved
putting in a small pressure bar. This roughly halved the speaking length of
the duplex thus raising the frequency produced by this section to a point
well above the problem. This was all done without reducing the energy of the
main speaking length....no compromise to the tone of that section.
Mark Bolsius
Canberra -Australia
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From: Ron Nossaman <nossaman@SOUTHWIND.NET>
To: pianotech@ptg.org
Subject: Re: S&S capo
Date: Mon, 22 Feb 1999 3:24 AM

 It is a string termination problem, but it's
at the capo. If there isn't sufficient string bearing angle across the
pressure bar (about 20 degrees), there will be a lot of energy leakage into
the front duplex, as you have noticed. This is a design problem resulting
from an attempt to get better sound out of an area in the scale that can't
produce the sound because of another design problem with the soundboard.
Reshaping the pressure bar may help, or may make it worse, but the fact is
that it was intended to make noise. Other pianos won't make exactly the same
noise because they don't have exactly the same configuration of bearing
angle, duplex length, and pressure bar shape. This was all discussed at
great length some time back. You might check the archives.

 
 Ron