I've got the three fronts and the sub sitting on top of the four feet high entertainment center. Last Saturday I was in the bedroom on the computer while the stereo was playing The Who's Behind Blue Eyes. All of a sudden I hear this crashing noise of from the living room. I go out there to find the houseplant that the wife had sat on top of the 15 inch high sub had fallen off and the porcelain plate under the plant had shattered and a dirty mess on the carpet. Well, I caught hell from her when she came home from work that evening. She said it's only three day pass new year (Chinese new year) and it was bad luck to break something like a plate (she's quite superstitious). Lesson learend: sub enclosure's vibration is violent enough to displace objects place on top of it. Must remember to remove plant next time I crank it. Hope this will help someone from experiencing the same fate.