Agraffe vs capo

[Delwin D Fandrich]

----- Original Message -----
From: "Phillip L Ford" <fordpiano@lycos.com>
To: <pianotech@ptg.org>
Sent: June 26, 2001 11:38 PM
Subject: Agraffe vs capo


> ----------------------------
> Would you advocate shorter duplex lengths and greater string deflection
angles to keep more energy in the speaking length?  What values would you
propose?  Do you think there would be tuning problems as a result of this?
I have tuned pianos with greater than 'normal' string angles at the capo and
they didn't render very well.  Would this be exaggerated by shorter duplex
lengths?
> ----------------------------

For this I must ask you to refer back to the articles I've already written
on the subject. They're in the Journals of several years back. And, sorry,
but as I told Terry, I don't have access to my collection just now and I
don't remember what the publication dates were. I wish now I'd kept track of
them, but....

And, your comments about excessive string deflection angles is well taken.
It's just as easy to go too far as it is to go too shallow. Excessive
deflection angles also lead to premature string breakage at the termination
point.



> ---------------------
> Would you give some examples of what the differences might be between an
efficient and inefficient agraffe system and between an efficient and
inefficient capo system?
> ----------------------

It usually boils down to sustain time. And sometimes to string noises. There
is not a lot of energy in the strings as they get shorter through the
treble. Any energy lost to the plate--whether it's in the form of an audible
string buzz, whistle, rattle, twang, or whatever, or simply quietly being
absorbed into the plate without a lot of fuss--is energy that is not
available to the soundboard system.

When I speak of efficiency of termination I am referring to the systems
ability to absolutely terminate the speaking length of the string and keep
virtually all of the energy reflected back into the speaking length. Any
movement, however slight, of the termination mechanism takes energy from the
string. And, as you say, some energy losses are inevitable.

The theoretical problem of agraffe termination is that the top of the
agraffe is not massive and it is slightly flexible--there is very little
metal (between and around the strings) to support it. Even the overhung
agraffes have this deficiency. But it is very easy to get good string
geometry with them. And it is easy to keep the duplex string segment short.
The capo d'astro bar has more mass and is a more solid part of the plate,
but good string geometry is a bit more difficult to obtain while keeping the
duplex string segment appropriately short.

As I said, you pays your money and takes your choice.



> ------------------------
> How do you feel about the system that Chickering used for a time.  A capo
bar with half agraffes screwed to the underside.  I always felt that this
system combined the best of both worlds.
> ------------------------

It's a good system, but it doesn't combine the best of both worlds. It does
provide positive string placement, but otherwise it shares all of the
positive and negative aspects of the capo d'astro bar/V-bar system. It's
just that the inverted agraffes replace the V-bar.

-- Del