[pianotech] Tuning the duplex sections

Joe DeFazio defaziomusic at verizon.net
Sat Mar 12 13:34:22 MST 2011


> From: "Don Mannino" <donmannino at ca.rr.com>
> Date: March 12, 2011 12:50:57 PM EST
> ...
> Another important factor which is, if I recall correctly, mentioned in the
> old patents is the benefit to the tone and longevity of the string from
> changing the wire movement at the capo from a bending action to a pivoting
> action.  When the duplex length is short or the angle very steep, the wire
> is effectively locked down against the capo.  When the angle is lower and
> the length is longer, the wire can rock or pivot slightly on the capo,
> reducing stress on the wire.


Thanks Don, for posting this;  it opened my eyes some.  

I was of course aware of the energy transfer past the capo, but visualizing it as a pivoting action really makes it clearer how this happens, and why it would also affect string breakage.

I would expect that the first and strongest wire displacement and pivot would be in the vertical direction immediately following hammer-string contact, while later and weaker displacements would migrate to the horizontal plane as the string oscillation changes.  I will try to make careful note of any subtle hourglass shaping in the cuts in the bottom of the capo bar the next time I reshape one (as opposed to more of a funnel shape).  In other words, the string cut might flare a little on both ends of the cut.  Has anyone ever noticed such?

Thanks,

Joe DeFazio
Pittsburgh
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