Pulsating string

Delwin D Fandrich pianobuilders@olynet.com
Thu, 21 May 1998 00:16:48 -0700


Not all of them, Jim.

I've found that the most common cause of this type of string malady is a "kinked" string.
This far down in the scale it's common enough that this is what I'd check out first. You
can't always see this, but if you run your fingers along its length you'll probably find a
spot where the stringer bent, twisted or kinked the string.

Regards,

Del

----------------------------------

Jim Coleman, Sr. wrote:

> Hi Arlie:
>
> There are several things which can cause a "pulsating sound from a plain
> steel string. They all have to do with contact points. The termination at
> the bridge is the most usual location. You have stated that it is solid at
> the bridge. A question may be asked, "Is the bridge pin solid?" "Does the
> string groove on the bridge surface extend beyond or in front of the bridge
> pin?" Those are the usual problems at that end. Sometimes an over sized
> bridge pin will solve this problem.
>
> Strings can have an insecure termination at the Agraffe or V-bar. The better
> rebuilders replace the Agraffes during rebuilding to avoid that problem. But
> problems can also exist due to irregular shape of the string. As a
> string is pulled up and down thru the V-bar, a flat can be formed on the
> string. Sometimes this flat may rotate slightly at its termination and cause
> what sounds like "pulsating". The other cause of insecurity at the V-bar is
> if the V-bar surface has a flat spot, where the string in motion bears upon
> the front edge of the flat when it is up and it bears upon the back edge of
> the flat when the string is in its downward excursion. Fixing the
> termination surface is the obvious answer in this case. Replacing the string
> is the other answer. Of course, any time you change a string, you bring in
> the insecurity of tuning for several months.
>
> The third place where problems of this nature can occur is along the
> speaking length of the string. This can be a drop of glue on the string, or
> contact of the string with the damper wire. A string moves in a vertically
> oriented elliptical motion. This vertical motion can oscillate back and
> forth over a few degrees range so that it might contact a damper wire only
> two or three times a second. It is simple to check visually for any damper
> wire contact, just move the damper head away from the string and see if
> the "pulsating" stops. If so, you need to adjust the strings or the damper
> wire. Also visually inspect for any foreign matter on the speaking length
> of the string.
>
> Jim Coleman, Sr.
>
> On Tue, 19 May 1998, Arlie D. Rauch wrote:
>
> > The client has a very nicely rebuilt 85-year-old Hazelton Bros. grand.  I
> > tuned it last fall and again recently.  She let me know a week later that
> > she was not satisfied with the tuning.  So I went back.
> >
> > The culprit was a pulse in the left string of the first unison immediately
> > above the bass/tenor break.  It developed that she really was satisfied
> > with the tuning, but she was hearing that pulse.  Apparently this problem
> > has been there before, but she thinks that last fall the pulse was gone
> > after I tuned the piano.
> >
> > The string is firmly against the bridge.  The other half of the string
> > which loops back to form the second string of the unison has a clear,
> > straight tone.
> >
> > Any suggestions as to the cause?  Any suggestions as to the solution?
> >
> > Is it possible that tuning the piano to A-441 might have eliminated the
> > pulse last fall?  Now it was tuned to A-440, both times per her
> > instructions.
> >
> > Thanks in advance.  I may not see the piano again until the end of summer.
> >
> > Arlie
> >
> > Arlie D. Rauch
> > Glendive, MT
> >
> > http://members.Tripod.com/~Turbooster
> >
> >
> >





This PTG archive page provided courtesy of Moy Piano Service, LLC