Let me say that Polk Subbies (I have the PSW 350) are absolutely no good as coffee tables. If you are thinking of buying one as such (which is the only reason my wife let me buy mine) you will be very disappointed.
My daughters DVD of KYLIE LIVE IN SYDNEY (DTS) played at half volume makes the subbie hop so much it ACTUALLY vibrated a glass (which you sit on coffee tables, don't you?) off, smashing it to a million pieces on the floor.
She was horrified! I was thrilled! Wow, what a buzz. I've heard these things will rattle the windows, but how about that. That bass line on the DVD was so powerful and pulsing, it was enough to jump a fairly heavy glass to the edge, and smash.
Hey, I love it!!!!!