compression vs rib crowning

[Farrell]

I've wondered much about this also. I think Andre Bolduc cuts a bit of arc into his ribs - but I don't remember for sure. I seem to think Nick Gravagne does also, but again, I'm not sure. I would be very interested to know what they do. Anyone know?

My curiosity extends to all that build soundboards for rebuilds. One basically never knows exactly what the original board design was. You can certainly determine board thickness, rib layout and dimensions, but you won't know the rib radii (or lack thereof) or the moisture content at rib glue-up. So it seems to me that anyone building a board of all the original dimensions with X rib radii and panel dried down to X% MC, is either an acoustical, mechanical, structural and/or materials engineer, is just guessing, or knows that what s/he is doing "usually works pretty good".

I hope to do a little work in the future building soundboards for local piano technicians/rebuilders. I know some of them will be stuck on the idea of "replacement with a soundboard of original design". In my mind this simply will not be possible (see above). So how does one decide how to mix original board/rib dimensions with pulling glue-up MC and rib radii out of your a$......er, a, out of thin air? I would like to perhaps turn this kind of work down, but as I really like to cut and glue spruce, and I have this need for income............

Terry Farrell
  
----- Original Message ----- 
From: "David Love" <davidlovepianos@earthlink.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: Monday, March 10, 2003 8:14 PM
Subject: Re: compression vs rib crowning


> Why is it that those who make soundboards (duplicate readymades for
> installation) don't make rib crowned boards?  Or do they?  The ones I know
> of seem to only make compression boards.
> 
> David Love
> davidlovepianos@earthlink.net
> 
> 
> > [Original Message]
> > From: Ron Nossaman <RNossaman@cox.net>
> > To: Pianotech <pianotech@ptg.org>; <davidlovepianos@earthlink.net>
> > Date: 3/10/2003 4:54:11 PM
> > Subject: Re: compression vs rib crowning
> >
> >
> > >Is the difference between rib and compression crowning one of tone or 
> > >longevity (or both).
> > >
> > >David Love
> >
> > Longevity, predictability, control. All in favor of rib crowning.
> >
> > Ron N
> 
> 
> 
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