I was listening to a dvd the other day (rob thomas dvd) the song was the last song on the album and I had it playing in 5.1 mode. I had it at a fairly decent volume, and as the piano kicked in I noticed a vibrating sound, so I went to each of the 7 speakers, (I have 5.1 plus 2 precence speaks) and I narrowed it down to the left precence, I was fidling around with it and noticed that also the left front speaker was doing it to. I put my ear down for a listen and it sounds like something inside the speaker near the inputs is vibrating? I put a cd in this time with a piano on it also. This time it still did it but had to be at a fairly loud volume for it to happen.
Any ideas???, is it possible that any speakers do this at some point in time if the source is loud enough?