Soundboard crowning...Frank

[Brian Trout]

Hi Frank,

I hope I'm not stepping out of bounds here, but I'll fill you in a bit as to
what the others might have been eluding to.

There have been discussions, sometimes at length, about the methodology used
to crown a soundboard.

There's the camp that says use straight ribs, dry the board out to 3% or so,
and let nature do it's thing when the ribs get glued on and the board soaks
up moisture.

There's the camp that says crown the ribs for the desired curvature, and
don't dry out the board nearly so much, perhaps to 6% or so.

And then there's the camp that says use a cull to press the crown into the
board as the ribs are being glued on.

Of course, there are many variations which include parts of all of the
above.  Indeed, it would be difficult, if not impossible, to do any one of
them to the total exclusion of the others.

>From the information I've gathered to date, it appears that Steinway uses
the first idea of crowning the soundboard using a straight rib and gluing it
to a very dry board.  (I honestly don't know if they use a caul setup?)

Baldwin, and many others use a crowned rib, and do not dry down the boards
so much, although there would still be a small compression crowning
component involved.

Still others I've been acquainted with will crown the rib somewhat, dry the
board to maybe 5% or so, and press the soundboard assembly into a caul,
making use of all three of the above concepts.

There are various arguments for and against all of the above, and it would
seem that although there's room to move about a bit, people tend to find
their nitch and stick pretty close to it.

The above being said, it probably got a few people kind of excited to see
your name pop up on the screen, knowing that you may have some knowledge of
the subject, not just from an engineering standpoint, but also an empirical
working standpoint.

I hope I've stated it well enough that you have a better feel for where the
question of "What do you think about it..." may have come from.

Just thought you might like a little background.  And if you have anything
you'd like to throw into the mix, your thoughts will certainly be welcomed.
(Not everyone will likely agree 100%, but that's ok.  We don't usually agree
100% on much of anything else anyway!  Just mention temperaments and you'll
get my drift...)

Regardless, Frank, I was certainly glad to see you posting to the list, and
I hope you'll consider doing it more regularly.  Nice to have you here.

Best wishes,

Brian Trout
Quarryville, PA
btrout@desupernet.net




----- Original Message -----
From: <PianoGuru@AOL.COM>
To: <pianotech@ptg.org>
Sent: Sunday, May 07, 2000 8:59 PM
Subject: Soundboard crowning


> In a message dated 5/7/00 5:51:13 AM Eastern Daylight Time,
richardb@c2i.net
> writes:
>
> <<  there has been a lot of talk about soundboards back and  forth
regarding
> the viability of the old style compression soundboard as opposed  to
boards
> that are more or less pressed over precurved ribs. >>
>
> Well, I hesitate to get involved in a discussion that I have not been a
party
> to from the beginning, but I will make a few observations.
>
> What is characterized as old-style or new-fangles is not necessarily so.
> Much of what we do today in building pianos is not far removed from the
way
> it was done 100 years ago.  It is not an either-or situation.  Most
> manufacturers today do cut a crown in the ribs, but we also rely on the
> effects of "natural" crowning.  We continually test ideas in experimental
> efforts to learn more about how we might build a better piano.  More often
> than not, the experiments raise more questions than they answer!
>
> Frank Emerson, engineer
> Mason & Hamlin
>
>