THE best subwoofer for 60/40 HT/2CH?

I looked around a lot for subs and I ended up buying an NHT SubTwo. They use two ten inch long throw drivers so they go damned loud but can move fast enough to keep up with music. They are $1200 with an external crossover, and if you want to spend about $900 more you can buy a second of the actual sub and run it off of the same crossover for stereo subs. My suggestion is to find an NHT dealer and take a listen. Also if they only have a SubOne, it is not nearly as nice so don't bother with it.

40 hertz is not 40 hertz. That is a count of how many cycles per second are made. It is a count. It is the same as saying a car made it one hundred miles in two hours. That means it averaged 50 miles per hour, not that it was always going fifty miles an hour. The physical cone of a speaker requires time to stop and reverse direction when it reaches the end of its throw (range of movement). More responsive, faster subs can make that transition master. The best analogy is that a graph of the movement of the cone looks more like a square wave than a sine wave. That is why Paradigm uses a servo motor to force the cone back into place when necessary in their top of the line Servo-15. As for NHT not making serious subs, that was true in the past, their subs were deficient, but the SubTwo was when that changed. The best advice is go listen to as many subs as you can.