Dampers

[Don Mannino]

Laurence Beach wrote:

>> . . .  I have been trying to mute out the last lingering harmonics of
an upright on the first of the trichords at the copper/steel break.  I've
tried an oversized trichord damper, as well as various combinations of block
and trichords.  I've tried moving the damper up and down all over the
place, but to no avail.  I have it pretty good now, and few would
complain about it, but there is still that last lingering harmonic that
lasts a fraction of a second.  . .<<

Laurence,

Lightly mark the string of the offending unison with chalk at each end of the
damper blocks / wedges. Pull the action, and using the edge of a rubber mute (or
something similar), lightly mute the string at each chalk mark and pluck the
string. One of the chalk marks will probably correspond to the harmonic you are
hearing leak through.

If it doesn't match up, then find where the offending harmonic's node actually
is, and try eliminating the felt from that node, if possible.

I have occasionally had good luck using one long trichord wedge, trimmed as long
as the bass strings will allow, to try to get maximum area on the string and
eliminate extra pressure on a node somewhere.

Sometimes old pianos are just a little weak in the springs, too. Try
strengthening the spring a little. Don't leave just one spring strong, of course
- you'll have to decide whether to strengthen more springs after you hear the
results on your problem note.

I'm presuming that the leakeage is on all three strings to some degree. If it's
only on one, then the problem lies in either the string leveling, string
spacing, or uneven cutting of a wedge felt.

One last thought. Bass dampers sometimes ring on because of impedence
mismatching (probably incorrect terminology, but it works for me). It doesn't
usually apply to treble wire, but why not try changing it.  Strengthening the
spring might do it, or try repinning the damper lever center tighter (measure 6
to 8 grams at the flange screw hole without the spring), or if the center is
already tight enough (swallow hard - flaming may follow!) clip a fishing weight
to the damper wire just underneath the damper head. This works better in heavy
wound strings than plain wire, but it's worth a try if nothing else works. Won't
affect the touch like stronger springs, either.

Don Mannino RPT
74473.624@compuserve.com