Best Subwoofer?

I own a REL Q100E and let me tell you, It is clean smooth bass. The price is higher because IT IS better. I too thought they were expensive, but now I am convinved.

Probably the best sub for music is REL. These subs use a balanced speaker level input direct from the amp so that they blend seamlessly with your main speakers. They are the fastest and most accurate sub that I have heard. They also have the best system for adjusting the crossover point. I have the stadium II model and it is the best out of the last five subs that I have had. It definitely is more expensive, but the cabinetry is also one of the nice things that attract me to these subs. The only other one that I have not heard that may have an edge is the new very pricey Aerial sub that has been getting great reviews.

It is a passive sub so you need a really juicy amp (I use a QSC Powerlight 1.8), but the Whise Profunder 320 is God-like is its presentation. Subtle when it needs to be and freakin' intimidating when you want it to be. As good as it is, you can still construct a sub that is as good, if not better, on your own for much less money.

I've been very impressed with the vandersteen 2W series subwoofers. Outboard crossover makes for very seamless integration with good quality mains pair. Work best in stereo pairs, of course, and can drive all but the largest rooms to any reasonable level. Tight and precise. Adjustable "Q" on the newer line. Kinda difficult to find good used ones, however (in my experience). Even new, reasonably priced.

I just acquired a Definitive Technology PF15TL+ sub. For $700 list, I am truly amazed. This baby sports a 500w amp and 15" woofer - a vast speed improvement over the PF15TL version. I cranked up No Mystery by Return To Forever, and my neighbor was rendered impotent for three days(?). Honestly, after auditioning B&W, Phase Tech, and Velodyne, I was sold on the Def Tech for sound vs. value. GOOD LUCK!