THUD

[S. Brady]

John,

If you find it isn't a keyframe/shift lever noise, check to see if the
sound gets better when you put firm pressure on the bridge cap at the end
of the section. If it does, let down the tension on those notes and
you'll probably find a loose glue joint between cap and bridge body. 

Another thing to look at is clearance between the bridge and the plate. If
the bridge is touching the plate, you'll get a very strange sound.

Good luck,

Steve



On Tue, 21 Nov 2000, John D. Chapman wrote:

> 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
> 
> 


_________________________________________________

Steve Brady, RPT
Head Piano Technician, University of Washington
Editor, Piano Technicians Journal