Interesting. This may be superfluous, but I would like to mention that some of the best-sounding old upright pianos I have seen have very wide, shallow ribs. And no cracks in the still very "live" boards. Knabe. Ivers and Pond. Mason. Not intending to muddy things here. I believe in and support the idea of rib-crowning. But how did these allegedly CC boards survive in Georgia for 100 years so well? Lots of varnish? Thump --- David Love <davidlovepianos@comcast.net> wrote: > 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 > > > _______________________________________________ > pianotech list info: > https://www.moypiano.com/resources/#archives > __________________________________ Do you Yahoo!? Yahoo! Mail - now with 250MB free storage. Learn more. http://info.mail.yahoo.com/mail_250
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