On Apr 23, 2006, at 7:54 AM, Ric Brekne wrote: > I dont think one actually does need crown. That could be true, given the number of ways to efficiently couple to the strings to the "bridge", which have already been suggested in this thread. However that would ignore the wonderful elasticity of spruce, which would seem a shame. I mean, the string plane is elastic, so why couple it to an inert diaphragm? (Well not completely inert, but at the small excursions the string plane normal subject a board panel to, a flat board wouldn't get too badly "bent out of shape". Thus, its elasticity would hardly get woken up.) > Del seems to think that crown was an accident to begin with, and > tho I am not sure I would go that far... Del does make a good point. If t were the idea of an engineer or of a factory's R&D department, there would be a patent on it (plus accompanying sales hoopla) in the historical record. Del has found none. I'd go along with Del, that it was an inadvertency, the by-product of large assembly and hide glue. It became accepted by testing the converse, waiting unto a rib-glued board had fully returned to ambient EMC, then trimming the excess so it would once again fit inside the rim. > it seems to me that all you need is adequate downbearing support > and a good combination of mass and stiffness. Seems to me that the only reason we're worrying about adequate downbearing support against the string load or a board panel which is flat to begin with, is the fear that the downbearing of the strings (being borne up into by the bridge height) would push the panel through flat into a negative crown. But wouldn't the string plane only push the board until the string plane itself flattened out?. I'm guessing that negative crown with negative bearing would produce the same pair of opposing springs (board panel plus string plane) that we all grew up calling home, with positive crown and positive downbearing. You'd enjoy the same mechanical advantage either way. (You'd just have to toss out bridge pins as a coupling mechanism.) On Apr 23, 2006, at 11:15 AM, Ron Nossaman wrote: > Then you'd have a no crown no bearing piano that works, but still > sounds somewhat different than we're used to, which isn't > necessarily bad. "Ladies and Gentlemen, over in this corner, wearing the purple shorts, we have...." a no crown no bearing piano that works, but still sounds somewhat different than we're used to, which isn't necessarily bad........ .........but not something I'd bet on when it goes up against the reigning champ, a crowned board ("Spring'o'Spruce™") with appropriate bearing. BTW, many thanks to the Boston Chapter for its one-day session with Del yesterday. Can you tell, instantly I'm an expert with opinions. Mr. Bill "No one builds the *perfect* piano, you can only remove the obstacles to that perfection during the building." ...........LaRoy Edwards, Yamaha International Corp +++++++++++++++++++++
This PTG archive page provided courtesy of Moy Piano Service, LLC