<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; = charset=windows-1252"> <META content="MSHTML 6.00.2800.1106" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY> <DIV>This is what your soundboard wants to do when exposed to high = humidity. Below is a photo of my mechanical moisture content (MC) meter. The = wooden part is a 4-foot long by 4-inch wide chunk of soundboard panel. The = panel is about 3/8 inch thick and has two ribs on the back (bottom in this photo) = that are about 3/8-inch thick by 3/4-inch wide. The ribs were glued on when = the panel and ribs were flat and at about 4% or 5% MC. The meter has = been in an 85% to 89% RH environment for three days now. It seems to have nearly stabilized. I did not measure the crown, but as you can see it is = somewhere around 6 to 8 inches.</DIV> <DIV> </DIV> <DIV> <SPAN id=__#Ath#SignaturePos__></SPAN> <IMG alt="" = hspace=0 src="cid:000701c2f66c$d7c66700$abb42341@tampabay.rr.com" = align=baseline border=0></DIV> <DIV> </DIV> <DIV>Soundboard panels in pianos exposed to high humidity are trying to = do what you see above. The stiff ribs and string downbearing pressure keep it = from actually developing 8 inches of crown. And instead of being able to = expand and produce this kind of crown, the soundboard simply crushes. No wonder = soundboard panels develop pressure ridges and then cracks when they dry back down! = The scale on the left goes from about 5.5% MC to about 8.5% MC. The panel = should be in the range of 18% MC in this photo.</DIV> <DIV> </DIV> <DIV>Fun stuff!</DIV> <DIV> </DIV> <DIV>Terry Farrell</DIV></BODY></HTML>