Floating soundboard at top

[Delwin D. Fandrich]

----- Original Message -----
From: "Phillip Ford" <fordpiano@earthlink.net>
To: <pianotech@ptg.org>
Sent: Monday, March 31, 2003 3:55 PM
Subject: Floating soundboard at top


> I currently have a small Bechstein grand in the shop.  Along the right
edge (the straight edge perpendicular to the bridge line at the top end)
there is a rib glued to the underside of the board but the rib and board are
not attached to the rim along this edge.  This would seem to be at odds with
the idea that things should be stiff up at the top end.  The sound quality
at the top is not superb, but not bad either.
>
> With the talk of undercut bridges at the top end and keeping the bridge
off the liner or bellyrail, I got to wondering if anyone had tried floating
the soundboard along the right end of the front edge (where the bridge would
run on to the liner if it was not undercut).
-----------------

Yes. Several times. If the tenor bridge ends up overly close to the rim I'll
float it. It is necessary to keep the impedance reasonably high up there,
but you don't want to make the thing completely rigid either.

I use a floating "liner," that is, a rib-like member running from the
bellyrail soundboard liner back to the start of the rim corner. The size of
this member varies depending on its length. It is placed about two or three
mm from the inside of the inner rim. The soundboard extends to the edge of
this member leaving a gap between it and the rim. Often the end of the
bridge will overlap this member.

Del

Del