I agree. It has occurred to me however that a rib crowned board is a far distance from a pure CC> crowned board in that a rib crowned board depending on the stiffness of the ribs is going to be getting a good portion of its strength from the rib structure alone due to crowning and increased beam height. How far one goes with that may blur the distinction between what we are calling a RC & S board and a rib crowned board. A board ribbed at only 6% is not all that dependent on much of its integral strength/resistance to down bearing force from compression yet it exhibits some very non-linear characteristics similar to its C.C. cousin that I find fairly predictable. The tell all clues to me are how stiff a hammer is required to make it move. Dale S. Erwin www.Erwinspiano.com 209-577-8397 -----Original Message----- From: Dale Erwin <erwinspiano at aol.com> To: pianotech at ptg.org Sent: Thu, Jul 15, 2010 1:12 pm Subject: Re: [pianotech] soundboard grain angle vs "faux"stiffness Having flirted with tap dancing on glass I am able to use the Ronsen Products on our rib crowned boards. But we rib at approx 6% for rib crowned stuff. The difference in types of stiffness is an interesting idea. So,isn't stiff just ...stiff? Dale S. Erwin I understand what you were saying. I'm just not that sure grain angle has all that much to do with hammer hardness tolerance without some experience. I do know that folks making rib crowned boards with a higher level of panel compression are using Abels, Renner Blues, and other such rocks successfully. > I also think that this "stiffening" behaves different tonally than the > stiffening created by a CC board that has hit its compression limit. I think these are entirely different critters than CC boards, in how they work. Ron N -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100715/4c04691b/attachment.htm>
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