Subwoofer/Amplifier

[nothing.sound]

Hey guys. Just a couple of questions and thoughts. I'm always trying to get the best out of my system and learn as much as I can about calibrating my sound system and t.v. so I just have a couple of things I was wondering about. Here is a link to the subwoffer I have.

http://www.energy-speakers.com/na-en...pecifications/

This sub states also that it is an amplifier as well. I'm kind of confused on the whole amplifier thing. The idea is to have a seperate amp for your diferrent frequencies right ? (high's and lows?) So can I use this somehow to improve my sound.

Also on my receiver(yamaha 663) I have the option to tweak each individual speaker. It's in the equalizer menu. It list different hrtz and has the option to change the decibal output. How do I know what to set these at?? Will the autp set-up fix those fro me?? Because I never got the mic with mine.
Thanks guys.