Agraffe tuning easier or not?

[Delwin D Fandrich]

----- Original Message -----
From: "phillip l ford" <fordpiano@lycos.com>
To: <pianotech@ptg.org>
Sent: June 26, 2001 5:46 PM
Subject: Re: Agraffe tuning easier or not?


> ------------------
> Why do you say that the Sohmer and Heintzman designs are taken to an
illogical extreme?  I haven't heard a broad sampling of these pianos but of
the ones that I have heard I thought the top ends were pretty nice.  I
attributed that partly to the connected capo.
> ------------------

Both were very difficult plates to cast and machine. Any improvement in
actual performance due to this feature is so small as to be virtually, if
not in fact, undetectable. While it is possible to measure some movement of
the capo d'astro bar in response to both the hammer impact against the
string and to the vibrating string, it is doubtful that the loss of audible
energy to this alone is either detectable by ear or measurable by machine.

I have heard some Sohmer and Heintzman grands with this feature that had
quite nice treble sections and some that had quite poor treble sections. I'd
look elsewhere for the reasons.

If you'd like to couple the capo d'astro bar to the pinblock panel, the
Baldwin system of individual termination pieces with a machine screw going
to either is a better solution. Even though the part itself is rather costly
it is probably still easier and more economical than either the Sohmer or
the Heintzman system.



> ------------------
> It seems that there is going to be some inevitable 'leakage' past the capo
bar or agraffe.  So the string portion on the side of the capo opposite the
speaking length is going to be moving.  You say that energy is being lost by
having a tuned aliquot design. Do you feel that less energy would be lost by
having a detuned aliquot design or by having this section damped out (felted
out) altogether?
> -------------------

No. You don't want it to get there at all. Once the energy is there, damping
it out just makes a bad situation worse.

It is easily possible to design a string termination system that keeps the
energy in the speaking portion of the string until it is transferred into
the soundboard system. For examples look at the typical upright design.
Simple and effective. Keeps the string angles reasonable and short. No noise
and no tricky work required on the V-bar except with the most sloppy plate
castings. Geometry wise this is a bit tricky to pull off on a grand plate,
but there are other ways of accomplishing the same thing.



> -------------------
> Why is the Baldwin design inherently inefficient?
> -------------------

The string angles are too shallow and the duplex length is too long. (OK,
those with the back-bearing riser reversed are better.) Otherwise it's a
great system.

-- Del