John... others Been thinking a bit on this idea that RC and CC boards can be made to have some sort of equality about them. You say, and I've heard this before, that a panel with same thickness, and same dimensioned ribs, with same crown will sound the same. But for a CC board to have the same crown as a RC board with same dimensioned ribs and same panel thickness, the panel must be under significantly greater compression then the RC board... yes ? If its under more compression and all these other moments are equal.. is it not then more stiff then the RC board. And when down bearing is applied does not this further change the situation with regards to stiffness. When I think about it.. the only way you could achieve same stiffness for same panel thickness and same rib dimensions is to guestimate what amount of crown would result in same stiffness for equal bearing... Yes ??? And even if such sameness was easily achieved... it rather applies only as long as the climate remains static... no ?? Thanks for your thoughts RicB John Hartman wrote: > > Phillip Ford wrote: > And I haven't yet become personally convinced that a RC > > soundboard can produce this. > > Phil, > If I understand you right, you don't think a Rib Crowned board can be > built to sound like a Panel Crowned board. If I have this right I say I > can't agree. If you make the board with the same sized ribs, the same > crown, the same panel thickness and and they both have the some bearing > then I believe they will sound the same. They will have the same mass > and stiffness and therefor the same acoustical properties. > > John Hartman RPT > > John Hartman Pianos [link redacted at request of site owner - Jul 25, 2015] > Rebuilding Steinway and Mason & Hamlin > Grand Pianos Since 1979 > > Piano Technicians Journal > Journal Illustrator/Contributing Editor [link redacted at request of site owner - Jul 25, 2015] > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html http://www.hf.uib.no/grieg/personer/cv_RB.html
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