<HTML>Hello Clyde, This summer = in my area we had so much rain, I didn't have to water my lawn the whole sum= mer. Even with a DC system I saw some pianos pitch go slightly sharp. Howeve= r, many pianos without the system were at A447. Also, It's a good ide= a in institutions to put the backcovers on them. The pianos are usually in t= he middle of the room with the soundboard more exposed that a private home w= ith the piano up against a wall. Hope you feel better.   Bob Russell, RPT</HTML>