Soundboard Edges

[Ron Nossaman]

>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