Soundboard

[Delwin D Fandrich]

----- Original Message -----
From: Matthew Todd <mtodd@pianotech88.com>
To: <pianotech@ptg.org>
Sent: Sunday, October 31, 1999 2:13 PM
Subject: Soundboard


> Does a soundboard in grands and uprights consists of several planks of
> wood, or just one piece of wood the entire shape of the soundboard?
>
>
> Matthew
>
---------------------------------------------------------------

Come on, guys.  Let's assume that this is a legitimate question.

Soundboard panels in all pianos are made of individual pieces of wood glued
together to make up the panel whole.  (Laminated panels, of course, are a
whole other subject....)

The "ideal" width of these boards has long been the subject of some debate.
In the US the practice has traditionally been to make all of the individual
boards approximately the same width.  Usually somewhere between 75 mm and
100 mm.  Our soundboards are made of Sitka spruce boards that vary between
90 mm and 100 mm in width.  We start with boards that are 100 mm in width
and occasionally have to trim one side to remove a flaw of some type.

We are now discussing the eventual probability of being forced to drop this
to around 75 mm.  It is becoming increasingly difficult to come up with wood
boards that are wide enough to meet the starting width of 100 mm.

The European builders don't seem to be as picky about this.  The soundboard
factory we visited in Italy this summer had stacks of panels for both
verticals and grands made of boards that varied in width from about 50 mm to
100 mm in width.  I asked about this and was told that they follow the piano
manufacturers specifications on this and that the customer simply did not
specify this.

Does it matter?  I hardly think so.  At least not with the rib-crowned
soundboard design that we use.  In fact, the specification of soundboard
lumber in general is way overdone and is largely driven by piano marketing
forces.  While the traditional compression-crowned soundboard panels do
place an abnormal degree of compressive stress on the wood used -- these
boards are best made with wood having relatively tight and consistent
grain -- with all other crowning processes the aesthetic characteristics of
the wood used really doesn't  matter all that much.  The wood should be
relatively light weight and as stiff as is practical.  (Our preference for
Sitka spruce is based on this.  On average, it is the stiffest -- for its
weight -- of all of the North American spruces.)

We throw away quite a lot of perfectly good wood that we have spent a
fortune on simply because it doesn't meet some artificial expectation of
aesthetic perfection.  Actually between 1/2 and 2/3 of what we buy.  (Well,
we don't throw it away, exactly.  But we can't use it for soundboards.)  All
of this selection does make for a very pretty soundboard, but from an
acoustic standpoint, it is all rather silly.

Regards
Del
Delwin D Fandrich
Piano Designer & Builder
Hoquiam, Washington  USA
E.mail:  pianobuilders@olynet.com
Web Site:  http://pianobuilders.olynet.com/