<HTML> <TT>Thanks, Brian for the new voice in this thread. However, while the available lumber stock may be declining, I would disagree that new soundboard panels/planks are any worse than 100 or 150 years ago, but perhaps this reflects better selection and definitely at much higher cost.</TT><TT></TT> <TT>I posted some time ago the following two references in the properties of spruce: "On Measuring Wood Properties," by M.E. McIntyre and J. Woodhouse in the Journal of the Catgut Acoustical Society #42, 43 and 45, and "Violin Woods: A New Look" by Alex L. Shigo and Karl Roy, University of New Hampshire, 1983. Noteably, the latter has a photo of spruce originating in China, while not citing species or any properties, the sample _looks_ very tight-grained.</TT><TT></TT> <TT>The soft, summer growth wood indeed is more easily compressed to failure and expands more, and the wood shrinkage figures I have are averages generalized to all applications; specifically, however, the wood with medium grain density is what this thread focuses on, since controllable expansion should be an issue for CC boards and strength and lightness is for both CC and RC boards (see Del Fandrich, "Soundboard Technology," Text for PianoTalk #2, Feb. 1995: <A HREF="http://www.olynet.com/users/pianobuilders/soundboards.html">http://www.olynet.com/users/pianobuilders/soundboards.html</A>) [...I am in no way associated or affiliated with...].</TT><TT></TT> <TT>As for my own understanding of the subject, the unshaped CC ribs as Frank Weston describes are considerably more _deformed_ to accomplish the same profile of an RC assembly; while the glue holds and the cellular structure of the soundboard panels remains intact, this should present little problem. But as failures progress, the tendency of these flat ribs is toward flat where the shaped ribs maintain crown longer.</TT><TT></TT> <TT>I seem to be adept at killing threads, but I hope not to do so with this one since I'll be rib-crowning my first piano soundboard in the next week or so.</TT><TT></TT> <TT>Clark "the Thread-Killer" 'Pianaccione'</TT><TT></TT> <TT>"You're lying - this thing's 400 years old" - Ray Vaillancourt, alias Hatso</TT></HTML>