Piano tone changing with age

[Delwin D Fandrich]

----- Original Message -----
From: "Richard Brekne" <rbrekne@broadpark.no>
To: <pianotech@ptg.org>
Sent: June 04, 2001 2:28 AM
Subject: Re: Fw: It won't be a Steinway anymore!/soundboards improving with
age?


> Who shares what position is really not so important... whats interesting
to me
> is that all of these positions are supported by subjective observation
only.

Well, not exactly. Unless you're of the group that questions the noise
making ability of a tree falling in the forest when there is no one (human,
that is) around to hear it.

Of course the tone quality of a piano (soundboard) changes over time. (Once
again might I refer the reader back to those Journal articles!) How much the
tone quality changes, and whether those changes are for better or worse, is
a function of how the soundboard is made -- i.e., how it is crowned -- and
how it is installed and how it is loaded.

In the so-called 'modern' piano part of the soundboard assembly stiffness --
as it is installed in the working piano -- is the result of a curved
(crowned) soundboard that is functioning as a pre-loaded spring. (Pre-loaded
by virtue of some amount of string bearing pressing against the upward curve
of the board forcing it partially flat by some amount.) As long as the
soundboard is strained by the downforce of the string plane there will be
some portion of the soundboard under compression and some other portion
under tension. As long as wood is bound to obey the various laws of physics
the wood cells under compression will be subject to compression set and the
wood cells under tension will be subject to a plastic deformation known as
creep.

As the wood cells physically change over time the stiffness of the
soundboard panel will also be changing -- it will be decreasing. Whether
this change will make the piano (soundboard) sound 'better' or 'worse'
depends partly on our defination of 'good tone quality' and on the physical
characteristics of the soundboard panel as it was installed. If the
soundboard was a bit on the stiff side originally it will loosen up and
become somewhat more responsive to energy at (relatively) lower frequencies.
We would probably say this piano's tone has improved with age -- André will
probably say it is sounding more 'mellow and creamy.' If the soundboard
started out life just right then the tone quality will become increasingly
percussive over the years and most of us will say the tone quality is
getting worse with age.

There are several things we can do to prolong the period of 'just right.'
Experience has taught us that rib-crowned soundboard assemblies tend to hold
their crown longer than those that are compression-crowned. For whatever
reasons soundboards with more ribs (each made smaller to compensate for the
larger number of ribs) tend to hold crown longer than soundboards with fewer
ribs.

Personally, I try to install the board so it is just a bit on the stiff
side. That way in roughly six months to a year it will have loosened up just
to the point that I like and will hold about that amount of stiffness for a
considerable amount of time.

Regards,

Del