I own a Velodyne SPL 1200R for the past 2 years. Very good sealed sub-woofer. Bass is very tight, punchy, excellent speed and I enjoy it. It comes with an auto setup/config mechanism which is also pretty useful. Velodyne makes one of the best ( SVS, Hu, Rel, Deftech Supercubes, MK etc are others) subs in the world. Their DD range subs have got pretty good reviews. As with any other audio components, audition before you buy. Good luck.