S&S capo

[Ron Nossaman]

At 01:43 PM 2/19/99 -0500, you wrote:
>dear list,
>
>we have a nice new S&S D here at the university that has a small problem
>that i am not sure how to address.  at the point in the treble where the
>capo begins i am getting a lot of noise from the non-speking length between
>the capo and the v-bar.  it's not "a lot" of noise but more than i like.  i
>have checked all the usual suspects; string level, hammer fit, bridge pins,
>strings seated, etc.  what i notice is that there is a ton of energy
>comming over the capo and into this length.  if i put my finger on that
>non-speaking length and play the note, the tone is dead.  i tried this on
>other pianos and i don't notice the same effect.  on a hard blow i am
>getting a sizzle from this section as if the string level was bad.  what's
>the deal?  should the non-speaking length be getting this much vibration
>through the capo?  why does muting that length deaden the tone so much more
>than other, similar pianos?  am i missing the obvious?
>
>thanks for your help,
>chris
>
>-Christopher D. Purdy R.P.T.   School of Music  Ohio University  Athens OH
>


Sounds to me like you are a victim of "tuned" front duplex noise. It's
unlikely to have anything to do with string level and hammer mating and
voicing, and certainly not the bridge pins and string seating (if the noise
stops when you touch the front duplex section, it's probably not originating
at the other end of the piano). 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