This is a mystery to me. This problem seems to have appeared out of nowhere. My Paradigm Servo subwoofer has decided to make a thump sound for every time I switch (with or without remote) to a different input source on my RX V2200 reciever. This is especially annoying while navigating through DVD menus. I get a thump for every selection I make, except for the volume control. Heck, even the kids are yelling at me to make it stop. My first thought was that the connections may have come loose after so many years of the cool deep base, window shattering, rumbling but I've checked all the connections and re-tighten them but the problem persists. I'm thinking that this may not even be a speaker problem. Maybe I should be posting on the Reciever forums. If anyone has experienced this situation or has any clue whatsoever, please let me know. Thank you so much.