False Beats

[Ron Nossaman]

>Anyways... would be interested in hearing more justification for each of your
>reasonings.
>--
>Richard Brekne


Hi Richard,
Probably the first thing anyone ever told me about installing bridge pins
was that it was crucial that they be seated at the bottom of the hole. This
was supposed to improve the termination and minimize, if not actually
prevent, false beats. For a long time, I didn't question that until I
started playing around with false beats to try to establish a cause and
effect relationship for myself. What bothered me most about the "bottomed"
theory was that anything that critical in theory ought to be pretty obvious
in practice and that didn't seem to me to be the case. Years back, I had an
old grand in the shop and hadn't torn it down yet, so I thought I'd see
what I could break. I located a half dozen or so clean sounding strings
among a whole bunch of false beaters and did some experimentation. Choosing
a clean note, I tapped the bridge pin lightly with a hammer and punch. It
moved down a millimeter or so and seated. It hadn't been seated before but
sounded clean. It was also clean after seating. Trying a number of others
just like it produced similar results. Well, it didn't seem to do any harm,
I wonder if it will do any good. Choosing a beating string, I seated it's
front pin. The beat lessened. Aha, improvement! Trying others, I found that
some got pretty and clean, some were slightly improved, and others not
noticeably changed. So much for the first blush of success. Since that
procedure didn't seem all that conclusive to me, I chose a few more beaters
and *turned* the front pin about 20° to get an un-worn surface under the
string. That had approximately the same effect as tapping, but the pin
hadn't been seated at all! Aha again! Next, I played each note with the
turned pin, listened to the false beat, seated the pin, and listened again.
Seating again seemed to improve some of them, but the difference was to my
mind negligible. Aside from reinforcing the ever growing suspicion that my
mind is negligible, this seemed to indicate that getting the string out of
the old wear track in the pin was what made the most difference, whether by
turning or seating the pin. That, however, isn't the point here.

Seating bridge pins in the bottom of the hole may be beneficial, or it may
not. I just haven't seen or heard anything to indicate to me that it makes
a real difference. I have, however, seen and heard enough to convince me
that the wear track on the pin is a contributor. That's primarily why I
recommend tapping pins in slightly, instead of seating strings on bridges,
to try to minimize false beats in field work. I know this is old
installation stuff instead of the new we were discussion, but it ties in
and is all part of my reasoning.

I've tuned a lot of new to ten year old pianos with long pointed pins that
were originally bottomed out in their holes and filed on top that weren't
any cleaner - and occasionally much wilder - than my too deep holes with
pins driven to finished height bridges of similar ages and usage conditions. 

I have no doubt that Ron O knows things I don't, and I know I'm not too
alert at times, but If I'm doing it wrong, shouldn't I be able to hear the
problem?

Ron N