Soundboard Edges

[Farrell]

Aaarrrrgggggg! Silly me. You are right. It is not a dome, it is a tunnel!

So is that a qualified crazy????

Terry Farrell
  
----- Original Message ----- 
From: "Ron Nossaman" <RNossaman@KSCABLE.com>
To: <pianotech@ptg.org>
Sent: Saturday, February 16, 2002 8:02 PM
Subject: Re: Soundboard Edges


> >While driving to Mt. Tabot Missionary Baptist Church this morning I had to 
> >turn off the radio and try and come to grips with the edges of a new 
> >soundboard. Let's say you make a 60-foot rib-radiused board (60-foot - the 
> >radius, not size of the board). OK, so now you have this little dome with a 
> >height of maybe 3/8" or so in the middle. (Or maybe you make one with 
> >smaller radii, so you have more crown - whatever.) 
> 
> It isn't a dome though. How does putting ribs on a board crown it along the
> grain? Hint: it doesn't. 
> 
> 
> >So what gives? The soundboard I guess. 
> 
> Ding! That's right. And it does it easily and cheerfully.
> 
> 
> 
> > Would this relieve some undesirable tension 
> >and suddenly let the piano breathe and bloom with beautiful sounds? Or is it 
> >that the 1/8" or 1/4" or whatever we are talking about here just doesn't 
> >matter at all?
> 
> Realistically, within reasonable limits, it doesn't matter. If the board
> can adjust to the compression of panel expansion constrained by the ribs,
> and the addition of 600 lbs and up of string bearing, it won't notice a
> 1/4" deformation at the perimeter. You'll have to push the treble end and
> tail down a couple of inches just to glue and clamp the soundboard in. The
> wood adjusts, and it isn't a problem.
> 
> 
> >Now either you will say that I am crazy and all this is meaningless (which 
> >may well be the case), or......."well give it a try Terry, and let us know!"
> >
> >But what do you think..........?
> >
> >Terry Farrell
> 
> Ok, if you insist... you're crazy.
> 
> 
> Getting more qualified every day.
> 
> Ron N