Scaling breaks/dead notes

Keith A McGavern
Sun, 16 Jun 1996 09:39:41 -0500 (CDT)

>...I wonder what the theory behind
>it is and whoever "thunk" (sorry, couldn't help myself) it up?...

Nick Gravagne and I came up with a technical name for a device created to
eliminate a dead note sound at the tenor/treble break in a Wurlitzer
Vertical Grand back in June 1992.

That device exerted pressure on one of the ribs via a backpost, thereby
enhancing that dead sounding note to blend in with the rest.  We christened
the device with the honorable title "Anti-Node Dynamic Soundboard Adjuster"
(ANDSA)        :-)

What led us to come up with such a device you might be asking.  Using the
plucking test I knew this wasn't an action related problem.

Somehow, I eventually thought that maybe applying more pressure to the
soundboard from behind might increase the crown and downbearing slightly,
thereby introducing sustain in this dead sounding note.  So I had someone
play the note, while from the rear of the piano I pushed in various places
on the rib in the vicinity of where the note's strings crossed over the
bridge.  When I heard an actual improvement in the sustain at one location,
I created a piece of hardwood shaped to fit the rib and added a piece of
leather to keep it from marring the rib itself.

Then I drilled a hole through the backpost in the same vicinity to
accomodate a wood screw, filed the end of the screw flat to press against
the hardwood piece, used the screw to apply pressure to the piece of
hardwood, which applied pressure to the rib, up to the point where the
sustain returned, and then gave the screw an extra tweak for potential
humidity fluctuations.

Voila!  ANDSA, a distant relative of MENSA   :-), was born.

Keith A. McGavern, RPT
Oklahoma Baptist University
Shawnee, Oklahoma, USA

PS Back aways, Barney Ricca, Associate Member, gave an excellent technical
in Texas along these lines about node points.  Excellent class!

This PTG archive page provided courtesy of Moy Piano Service, LLC