<html> At 05:28 PM 05/05/2001 -0400, you wrote: <blockquote type=cite cite>Thanks, Jim, that's what I was trying to say in my post on fixing cracks in soundboards! Wally,  It seems to me that a board with numerous cracks would lose some of its power by > only the ribs transferring the vibrations from panel to panel without help > from the panels having solid connections to all the other panels otherwise. >  Said another way a board with 'continuity of surface' will perform better > than one without. > My view. > Jim Bryant (FL) > </blockquote> If you are going to look at it that way, then first compute the total surface area of the crack opening. Subtract that from the overall surface area (top and bottom) and that is the area moving the air. For the sake of illustration, a 36" x 36" section of board contains 1296 sq" on one side. A crack is about 1/64" x 30" (.016 x 30 = .048 sq inches). It would take ten of these cracks to produce a .480 sq" loss or only 1295.52 sq" of board moving the air in that section. A loss of .03% surface area for that many cracks. A board is larger than this illustration which further diminishes the percentage. Especially if the crack is not open at the bottom and you add the surface area of that, it then becomes a .015% loss. Less than 1% is a negligible loss.  For all intents and purposes a shim is cosmetic. I heard of a test where a 2" strip of board was removed from behind the bridge with no discernable loss. Shimming ain't what it's cracked up to be, Jon Page,   piano technician Harwich Port, Cape Cod, Mass. <a href="mailto:jonpage@mediaone.net" eudora="autourl">mailto:jonpage@mediaone.net</a> <a href="http://www.stanwoodpiano.com/" eudora="autourl">http://www.stanwoodpiano.com </a>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</html>