Oddly i've never had this happen before. Set up my RS210 cab and F1 head, and started band practice. Played a low E on my low B-string and poink... no big sound... dead, hollow, weak... Fiddled around for a while with it, but finally just lived without for the 3 hours. Debugged it in my head as either being a string gone bad, or a something trapping that specific frequency in the room. (Eb, E and F on that B-string were all weakish, but the E note was the deadest.) Got home after wife was in bed and changed the strings out to a new set, and this morning tried everything through the rig before I came in to work and everything sounds fine. So it was one or the other... string or room anomaly. I've had strings go bad like that in certain spots before, but I've never personally ran into an area in a room that was that specifically dead. What I was most worried about was that my Big Al 5 had acquired a deadspot on the 5th fret of the B-string... that would have been 'bad' :: shrug :: .