after-ring

[Delwin D Fandrich]

DICK BEATON wrote:

> Les..
> I've had the same experience with a Kimball.  There is no cure for that
> thing!               The dampers hit the wrong place on the strings...a
> node...so the only possible cure is to move the dampers up, but that will
> be in the way of the hammer, so it is a lousy piano design.
> Dick RPT
>
> ----------

Les & Dick,

I'm not convinced that with many of these problems it is just a matter of the dampers seating on the
wrong portion of the string. Unless a mistake has been made during the construction of the piano and
the dampers are sitting well below their normal home just below the hammers, all vertical dampers
work in the same general area on the strings. At least in modern pianos. In other words, they all
work with the same inherent disadvantages, yet in some pianos they work quite well and in others
they constantly give us trouble. After all of the right things have been done with felt shape, type
and density, and once all the right regulating and adjusting of things has been accomplished, if
there is still a damper bleed problem, then it is likely to be either a scale design problem or a
damper mass problem. (Keeping in mind that when I refer the the "scale design" I am talking about
design of the entire tone generating mechanism; the soundboard & ribs, the bridges, the plate and
strings, etc.)

Most often I have found that perpetually troublesome damper bleed in a specific area of a specific
piano model is due to energy being coupled from one bridge to the other along a rib. Usually from
the tenor to the bass. For example, if an A tenor string crosses the tenor bridge just over a
particular rib, and if that rib just happens to cross under the bass bridge at, or close to, the
spot where another A in the bass section also crosses over it, there is likely to be quite a lot of
"damper bleed." In this example, the bleed would typically come from the A in the bass that is
ringing at the fundamental frequency (or possibly some harmonic) of the A in the tenor. For obvious
reasons, smaller pianos are more susceptible to this malady than are larger pianos.

If this is the case, the problem can still be cured, but certainly not in the normal sense. It is
fixed by redesigning the rib scale and/or relocating the bridges on the soundboard. Just schedule a
little extra time for your next visit.

As I indicated above, if all else fails one other possibility comes to mind and that is a lack of
adequate mass in the damper head and lever assembly. For a discussion on that see the tail end of my
article on the subject in the December, 1995 Journal.

-- ddf