Soundboards

[Delwin D Fandrich]

----- Original Message -----
From: <ANRPiano@AOL.COM>
To: <pianotech@ptg.org>
Sent: April 21, 2000 6:20 AM
Subject: Re: Soundboards


> How does one go about measuring "internal friction?"

With a great deal of difficulty.  I don't know of anyone who tries, outside
of, perhaps, the National Forestry Labs.  Think of it as a damping factor.
With none, much of the really high frequency garbage gets produced along
with the good stuff.  With too much, some of the desirable upper partials
start to get dampened out.  Fortunately, there is a very broad range of
acceptability.



> Would it be greater in
> a laminate board because of the laminations?

It will be different.  How much will be determined by the type of wood -- or
other material -- used and on how it is used.



> Does the glue joint between the
> ribs and board come into this equation or is this a cellular thing?

It is a cellular thing.



> The stiffness of the SB assembly is determined to a large extent by the
cross
> sectional ratio of the ribs. Width in proportion to height. Right?
>
> How does one go about determining the best ratios?  In the "killer octave
> area" what changes are most helpful?

Trial and error.  Buy the piano and experiment.



> I know most original research in the piano field is now conducted by
> rebuilders such as those on this list.  I am not looking for any
proprietary
> information.  Just point me in the right direction to look.

Read everything you can get your hands on.  Study -- no, don't just look
them over briefly, STUDY -- the designs of every piano you rebuild and every
interesting piano you encounter in the field.  And I don't just mean the
great sounding ones.  You can learn a lot from the really bad ones as well.
Then start to work.

Del