Syed, although you say that you've checked and all speakers are working, I still question it. In the moving and storage process there were certainly chances for something to come loose, and your description of the sound would be consistent with one or more drivers not working. As was said, double check for the tightness of the connecting strips on the terminals. Connect the speaker wires to the top(mid and tweeter)terminals if they're now connected to the bottom ones. Does the problem affect both M60s equally? If none of the forgoing is helpful, can you open them up to check for a loose internal wire?
