I'm not sure that the rib crowned board necessarily uses ribs of more mass, rather they are taller and narrower instead of shorter and wider. David Love davidlovepianos@comcast.net -----Original Message----- From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Richard Brekne Sent: Sunday, January 23, 2005 1:59 PM To: Pianotech Subject: Re: circle of sound Erwinspiano@aol.com wrote: > > > Ron O. write > > Possibly, the ribs on the bigger pianos are also > quite heavy relative to their strength. The > Imperial ribs are nominally 30mm wide by 23 mm > high. > Hi Ron .O > If the Bozy had ribs 30 high by 23 wide ,which, is reverse of the > above, then perhaps a different tonal result at the higher dyanmic > levels would be more likely. Whadda ya think ? > My goodness this is a very flimsy rib for a massive piano but then > this to me would indicate a purely compression crowned board You touch on a point I've been scratchin my head about for 4 years now... relates to a disscussion between myself, Delwin, and Andre back then. How (if possible at all) a compression board... with smaller dimmensioned ribs and more reliance on the compression of the panel for stiffness can be made to yield the same... or nearly same acoustical results as a rib crowned board which uses larger dimensioned ribs to achieve the same stiffness. At best it would seem to me that their might be some RH level where the two might be somewhat similiar... but the requirement for greater rib mass in rib crowned assemblies alters the stiffness to mass ratio, and if its compensated in any sence of the word by less panel mass then at the very least the distribution of mass is quite different. Still looking for a good explanation here. > Dale Cheers RicB _______________________________________________ pianotech list info: https://www.moypiano.com/resources/#archives
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