THUD

[John D. Chapman]

Just tuned a S&S D brought in by the dealership for a Brahms concerto with
the symphony.  Notes 50,51,52,&53 (last four in agraff section, just above
A440) had an unpleasant pronounced THUD when played above forte.  This is
the same THUD which is always there lurking behind piano tone but usually
not dominating it.  I checked keyframe front, back, and glides, checked
for loose hammers, held up dampers heads by hand and played the note to
see if it was a damper problem and it was  not, checked damper upstop
rail, seated strings on bridge, reshaped hammers to that nice S&S pointy
shape, tried needling, tried juicing, switched a couple of hammers from a
few notes below where the sound is good just to see if it was a hammer
problem and it was not.  What have I missed?  The one thing I didn't do
which might have help diagnose the problem was to pull the action in and
out to change the strike point.  What do you think?

John D. Chapman RPT
Wake Forest University
Winston-Salem NC