Damper problems

[Yardbird47@aol.com]

There are plenty of noises to be weeded out durng the time when damper felts
are erasing piano tone. In fact the process is one of shaping the end of the
of the tone, and is complementary to the voicing work we do with hammers, to
shape the beginning of the tone. The slower the pianist seeks to set the
damper back down on the string, the longer we'll have to suffer whatever may
be laying therein.
Within hearing range (which is all of ten feet), the wheeze is the bane of
studio microphones and contemplative pianists. The "oink" will however travel
to the back of the hall. I hear the "oink" as tone disappearing into a thin
wisp (or "rat-tail") of high partials. It appears to come from a matting of
the fibers on the business end of a flat damper. The only thing which I've
found will reduce that squelching of the sound is a light combing of the
flats with some 220 sandpaper. (The weight of the damperheads by themselves
might even be a tad too heavy) I haven't found anything predictable about the
appearance of the delayed damping of high partials, although my survey of the
problem is pretty sparse due to the number of old uprights I still tune as a
rural technician.
The fundamental partials are definitely gone by the time the damping goes
into its rat-tail. But what is the special difficulty with the higher
partials. Do the tiny wavelengths lie better in the string's horizontal
(radial) mode of oscillation? Does a flat pad working horizontally miss an
increasing amount of oscillation as the partial wavelengths get smaller? Is
this because, with higher subdivision of the fundamental wavelength, more of
the total partial strength lives out of the particular partial whose antinode
is being damped?.
What makes the oink more pronounced in the Una Corda position? I've listened
to the damping of all three strings of a treble trichord, by muting two
immediately and then bringing the damper down on the third. It didn't point
to any particular one of the three strings as the source for the oink. BTW,
This test will show up the felts which can't damp simultaneously. For some
reason, hearing three dampings on a note at equal volume is never as annoying
as hearing 2.25 of them (the .25 is the sympathetic left string.). It's like
the slightly turning unison which always sounds worse in the U.C. position..
Unsynchronized damping in the wedges is taken care of by spreading the wedges
with Karen Robinson's squiding line, or by tweaking a wedge. In the flats,
you take a small implement with three voicing needles set close on the end,
you pick which area of the flat you want to expand, you delicately insert the
tool and rotate 5 degrees. Mind you, every once in a while I get paid for
doing this kind of work.

Bill Ballard RPT     "I gotta go ta woik...."
NH Chapter         Ian Shoales, Duck's Breath M. Theater