Piano tone changing with age

[Farrell]

"....wood faires, dancing around bonfires naked whilst throwing red ocra
into the
flames,,,,, and get to what little real facts there...."

Thes is not real? Hey, my wife if a witch. Where is the bonfire? Let's go
worship the wood fairies!

----- Original Message -----
From: "Richard Brekne" <rbrekne@broadpark.no>
To: <pianotech@ptg.org>
Sent: Tuesday, June 05, 2001 3:22 AM
Subject: Re: Piano tone changing with age




Delwin D Fandrich wrote:

> Richard Brekne wrote;
>
> > 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.

To which Del began his reply

>
> 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.

Which illicited an immediate grin .... that sounds like me alright...

> 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.

Sounds very reasonable.... course we also are dealing with exterior forces
most
notibly the climatic conditions.

> 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.

Nice straight forward description.... with no value judgements attached to
these
postulations. Fair enough.

> 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.
>

Now this I like... Note that Del doesnt say declaratively what is or isnt
good
piano sound... quite the opposite actually, and note that when using
descriptions of sound "colour" he alludes to what the subjective ear might
probably experience.

> 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

On the whole a welcome and balanced contribution to the whole thread. Thanks
muchly Del. You pretty much confine yourself to relateing piano tone to
stiffness in the board, (we are after all talking sound boards and ageing)
and
coupling stiffness to the condition of the wood cells. I assume you have
some
hard science to back this up... wouldnt be like you not to... But there are
still left many unanswered questions that may or may not contribute to how
wood
ages, how that affects sound... and what potential there is for this all.
That
is unless studies have also gone so far as to rule out all the other claims
we
have heard through the years.

I note in your reply to the wood resin post you declare that whole thinking
in
error. I wonder if you might explain further how that is in error. Again my
purpose is to attempt to weed through what seems to be a forest of
assumptions,
wood faires, dancing around bonfires naked whilst throwing red ocra into the
flames,,,,, and get to what little real facts there are relating to all
this.

In closing, thanks again for your underlining of the subjective nature of
"good
piano tone" in this kind of discussion.


--
Richard Brekne
RPT, N.P.T.F.
Bergen, Norway
mailto:rbrekne@broadpark.no