If you want the deepest, lowest, non boomy fast bass with realistic stereo sound then look into the TacT W410 corner subwoofer. This is the best of the best, but it has no amplifier (I'm using a pair of Bryston 7B-ST amps), and it has no crossover (I'm using a Marchand active crossover). Each subwoofer has four 10 inch drivers and easily goes down to 12Hz. Fair warning... tie down everything in the room. TacT has a smaller version with two 10 inch drivers and goes down to 16Hz. Keep in mind that you will need a 47 foot wall to fully develop the 12Hz, and a 35 foot wall to fully develop the 16Hz. Each W410 costs $4,000 and the half sized subwoofers cost $2,000. You can build the enclosures yourself with plans they provide. Each driver is about $125. You can really get a good deal by getting one of their prototypes. I got the W410 sub prototype for $700 instead of the usual $4,000. The catch is that it's black with no fancy wood.