Get a pair of Behringer professional amps for about 300 bucks or less per unit, set them to mono (bridging) and they will give you about 500 watts per side. You won't need a low pass filter unless you have a TT which rumbles like a hungry lion snoring and put on a floor which has the solidity of old bedsprings....
Here is the URL: http://www.behringer.com/A500/index.cfm?lang=eng
These things are built like a tank and used for this purpose sound amazing. I used them for good effect on my Gradient subs for quite a log time
Here is the URL: http://www.behringer.com/A500/index.cfm?lang=eng
These things are built like a tank and used for this purpose sound amazing. I used them for good effect on my Gradient subs for quite a log time