like to which sub would best suit my system. my system: onkyo sr 803 with speakers b&w 600 series. main use is of HT. i was thinking about the paradigm sub.
I owned a B&W ASW750 and had very poor results. I've heard very good things about that sub so I figure it wasn't a good match for my system. For HT only you would likely have good results with Hsu or Outlaw. If it's music you're concerned with it's an altogether different story.
There are better subwoofers than B&W but the Bowers and Wilkins subs do quite well for the money spent. What I want in a sub might not be what anyone else wants in a sub so I can only tell you what I hear from the B&W's that I find missing in most other subs for the same price (the most competitive to my ear, dollar for dollar, seem to be a few other British lines - obviously I prefer a British bottom but I haven't spent that much time listening to subwoofers).
The B&W subs typically have a more musical voicing than far too many subs marketed to the HT crowd. The ability to differentiate the low frequency instruments is far superior on B&W subs when I compare them to other more or less mass market brands. Kick drums are distinct from bass guitar or double bass and low piano notes stand apart from the mix. The B&W subs have a very good pacing to their output which moves the music forward with a sense the other musicians are listening to the bass line for their foundation. If the sound designer and music director have coordinated to use both elements to benefit the effect of the moment, the B&W pulls the listener along with the tension of the bass line. Most other subs are too dry or too sloppy to manage this as well. For a vented system the B&W's come very close to the sound of a sealed box, much closer than most of the competition would care to even attempt let alone manage. Low frequency detail is as good through the B&W's as I've heard for their price and dynamics are top notch within their price range without drawing attention away from the other eight or nine octaves of music. Since my HT use is more aligned with films that rely on music to move the storyline, rather than explosions, this type of sub suits me quite well. Even with action movies there is more time spent with the musical soundtrack than with explosions, so I would rather have a more musical sub rather than one that does explosions well and leaves the music to fend for itself.
What the B&W subs tend to not do well as someother lines is musical grunt. Not explosion type noise but musical grunt from rock or jazz bands. "Cream at Royal Albert Hall" is not served as well by the B&W subs as with some other brands. There is an over-riding politeness to the B&W subs that never allows them to play like it's twenty minutes to closing time. However, pulling Ginger Baker and Jack Bruce apart has never been so easy as when they are heard through a B&W sub. If you picked the B&W's for HT without a sub, you probably did so because of their bass response. Why mess with that?
There are better subs out there than B&W but I certainly wouldn't not consider them for this set up.