<HTML style="FONT-SIZE: x-small; FONT-FAMILY: MS Sans Serif"><HEAD> <META http-equiv=Content-Type content="text/html; charset=windows-1251"> <META content="MSHTML 6.00.2600.0" name=GENERATOR></HEAD> <BODY> <P> <DIV>I've been working for a couple of years with a teacher who periodically complains of the "top going sharp" on her Mason & Hamlin BB.</DIV> <DIV> </DIV> <DIV>Whenever I get there it's back to normal!</DIV> <DIV> </DIV> <DIV>There were some serious humidity issues, but a DampChaser system with a bottom cover seemed to solve that.  Then yesterday she called desperate "I've got concerts coming up and it's going sharp again!"</DIV> <DIV> </DIV> <DIV>Because of the long thread on this list I finally began to think "temperature." </DIV> <DIV> </DIV> <DIV>When I asked she said "I come in to practice early before the heat's on.  That's when it's sharp!"</DIV> <DIV> </DIV> <DIV>She never opens the lid, just the flap.  I think the Damp Chaser system keeps the inside warm, but the high treble is exposed enough to catch a chill, which goes away when the heat comes on.</DIV> <DIV> </DIV> <DIV>I think I'll ask her to blow warm air from a hair dryer in the treble end next time!</DIV> <DIV> </DIV> <DIV>Ed Sutton</DIV> <P></P></BODY></HTML>