I had to replace both woofers on my brand new EP500s. Both had bad rattles. On one the voice coil came unglued from the woofer cone causing the rattle. On the other, when I moved the woofer in and out it would not operate smoothly, thus I assume that was causing the rattle. Must have been a bad batch from China. The great Axiom folks sent me two new woofers and now everything is just fine. In fact, probably too good. My whole upstairs rattles when the kids are playing Halo 3 downstairs.

Don't die with a clean shop!