string ringing/buzzing

[Charles Neuman]

Here's my string problem:

It's not really a buzz. It's almost, but not quite, a "metalic ring".
It's more like a high pitched ringing that accompanies the note. It
happens in one or two treble notes. In one note it comes and goes. By the
way, the sound is really subtle, so I'd say I'm being somewhat picky here.
I don't know if I should expect every string on a piano to sound perfectly
all the time. On just about every piano I've ever played, I notice there's
always some buzz or ring somewhere.

Anyway here's what I've done: I am able to affect the sound (almost
eliminate it)  by using a three-string spacer and tapping to the left
and/or right between the V-bar and pressure bar. I forgot to mention it's
a vertical (M&H Model 50). In one note, the sound came back a little. In
another note, I lowered the tension some and tapped with the spacer and
got better results. If you have any techniques to recommend, or any
warnings, I'd appreciate it.

Reblitz says that if the ringing comes back after tapping a three-string
spacer, then the V- bar might need some sanding or pollishing. Would you
agree? The V-bar looks fine to me, but maybe some really fine sanding
would do something that I can't even see. Would you recommend any
techniques, especially for working on just one note? The sound is really
subtle, so I doubt I'd want to do anything that required lowering the
tension in all the strings.

I had lowered the pitch of the piano 4 cents when I tuned it. I'm curious
if the slightly reduced tension after the pitch drop could have caused
this. I noticed a few notes that made some subtle ringing sounds after the
tuning.  Most of them went away after some settling in. I'm a little
scared to play around with adjusting the pressure bar height, but I wonder
if that would help. (I have been warned never to do this with full
tension.) Another possibility is that when I lowered the tension, I
dragged some dust between the string and the pressure bar. Sounds
far-fetched.

Any ideas?

Thanks,

Charles

P.S. I should also mention that I'm especially sensitive to high pitched
sounds lately due to some hearing problems, which seems to be clearing up
(I described the hearing problems in a separate email today). However, I'm
convinved the subtle ringing I'm hearing in a note or two really DOES
exist.