Can someone tell me if the EP500 Sub is a "powered" sub? Or does power need to come from the amp or receiver? Sorry for what seems to be a dumb question. How does it compare to the EARTHQUAKE SUPERNOVA MKV-12 POWERED SUBWOOFER?

Alex Denon 3805 Panasonic S97 DVD 2 M80's 1 VP150 4 QS8's next 1 EP500 next Sanyo Z4