Neo,
Since Bob and Wolf (both pretty convincing contributors here) are providing conflicting advice, I'd suggest that you find a good high end HT installer/retailer and do an A/B comparison with Digital Room Correction and without it. That's a simple bypass button and a very clean A/B.
You've got to find the right showroom so that the sub placement is optimized prior to room correction EQ. Then, you can decide for yourself.
For the record, I've done that in my dedicated listening room with two different pairs of subs (Rythmik and Velodyne) and in my HT room with B&W subs. The positioning of the subs in the listening room was optimized both by ear and - on a second pass - with the aid of a real time analyzer. In the theater room, the position of the subs was largely dictated by the room layout, so there was much less flexibility in optimizing location.
In all cases, room correction made a dramatic improvement - to my ear. In fact, by my reckoning, no other change to my system over the last two decades has come close. But there's a caveat.: Since Wolf's mileage seems to vary from that conclusion, be aware that yours may, too. Which is why an audition at a retailer who can do it right is probably your best bet.
Marty
As to the active/passive (distortion) debate, that's a tougher A/B since most systems (that I know of) kill the sub output entirely when you remove the active low-cut filter from the main speakers. That means you'll probably have to re-wire the system before you can compare active crossing to passive which makes the judgement more difficult IME.
I find the theoretical arguments for actively crossing a system pretty compelling, but my experience suggests that it's very much case by case dependent upon the main speakers. I've done it both ways and had good success with both - but the best results I've gotten have come from actively crossed systems. If in doubt, I'd say cross actively but would note again that YMMV.
