While cruising walmart.com for some mini dvd discs for camcorder I saw an ad for a Pioneer 12" 600 watt peak subwoofer for $58. They had maybe 20 speakers, and several other subs.

They recommended an enclosure of 1.5 cubic feet. Sub has 91dB sensitivity (is higher better?). 4 ohm and 20 Hz to 4000 Hz and two coils so each channel of my receiver can be hooked up. Is an separate amp needed? Is a Crossover needed?

I just want to improve my bass (only have 10" woofers) and the wife will not let me turn my Sansui 9090dp above a few watts. (it is rated at 125w/ch at 8 ohms rms and is a real powerhouse not like some of these newer, wimpy receivers, this thing is 53 lb with a hugh power transformer)

Has anyone made a cabinet for one of these subs? Would just a sub and cabinet work?
Is a duct needed? Any plan source?

Charlie