Capo noise, where it comes from

[Michael Wathen 556-9565]

I'm not sure who wrote this because they didn't sign their name and the software
they use here will not allow me to see the individual's name, only Pianotech.

>I think Michael has pointed out that there is more to clean treble sound than
>just the shape of the capo bar. I too have had pianos that continued to zing
>after a "proper" shaping, even after string leveling, reshaping, and checking
>string deflection angles. I suspect capo bar smoothness is very important, but
>other factors include updraft angle, string tension, length of front duplex wire
>and diameter of wire, hammer hardness, as well as profile of the capo.
>
>Like Ron, I too have had the experience of eliminating string noise in the capo
>section by resorting to hammer voicing after all capo remedies failed. I felt
>like I was treating the symptoms instead of the problem by needling the hammers,
>since I could stop the noise by touching the front duplex section with a finger.
>However, some deep shoulder needling stopped it without appreciably changing the
>tone.

My point seems to be missed.  The question is where does the noise come from?
My belief is that it comes from the capo bar and that it is a symptom of a
larger problem that needs to be "dressed".  Yes, you may get rid of the noise
by voicing.  Yes, it may appear that it has not seriously affected the tone.
But, due to the reasons that I outlined in my first post on this subject I'm
willing to bet that were you to measure the difference you would in fact find
a discernible change.

Next, I fill that perhaps the most important aspect of this discussion is the
fact that there are to normal modes of vibration for the string, one horizontal
and the other vertical (Weinreich, Journal of Acoustical Society of America,
August 1977).  Our proof of this and the fact that it is a significant factor
for technicians is directly observable on a single string that is not correctly
seated on the bridge.  In this case the string supports to different frequencies
because the horizontal length terminates at the bridge pin while the vertical
length terminates somewhere behind the bridge pin on the bridge.  If we have a
problem with this case due to this existence of the horizontal motion of the
string then we should expect a problem with this same motion at the capo bar.
The capo bar needs to reflect the energy efficiently in the horizontal direction
or there will be a great energy lose at the capo bar as kinetic friction.