Percussive Tadashi

[Granholm Bros.]

List:

Today I tuned a Tadashi grand, probably less than 10 years old, with no
visible faults.  During the tuning, I noticed something I haven't
experience before, and I hope maybe someone out there can help me with it.

This piano makes a sound like a drum when the keys are played.   It's not a
dull thump or a crack like might come from a warped keyframe knocking on
the bed.  This is more of a "poom" sound, with a definite pitch (about that
of a tom-tom in a trap set), and about a half-second sustain.  No hint of a
rattle, just a poom.

I investigated further.  I thumped the bottom of the keybed with a closed
fist.  Poom.  I went around the rim, pounding with closed fist.  Poom.
Poom.  Things seemed to quiet down as I moved toward the back of the rim,
near the bass bridge, then liven up again as I continued around the rim...

This was my first time on the piano, and the customer wasn't home.  But
this intriges me, because in 15 years of tuning I've never heard anything
like it.  And in case I get asked to track it down, I need some ideas about
where to start looking.

Any suggestions?

John Granholm
Granholm Bros Piano Rejuvenations
Roseburg, OR
gbros@term.wanwb.net