Sub Question

I would never give up my pair of Vandersteen 2Wqs. These subwoofers blend seemlessly with my mains (now Ohms, but previously they blended equally well with my Vandersteen mains). Check my review of these in the review section. Properly executed and set up, a dedicated, powered subwoofer can do things that most full range speakers simply cannot. I suggest you read about them at the Vandersteen web site. Their design is somewhat unique and addresses two major issues of subwoofers: crossover and placement. I got mine used here on Audiogon, but even new, they are a fantastic value for a music-oriented sub (as opposed to home theater), IMHO.

Rythmik Audio in Austin Texas.....Gread

Thanks for the responses so far, but I don't think we have adressed my original question. Does a sub indirectly help or improve the sound or frequencies by taking pressure off of the speakers?

Indirectly, yes. The sub by itself does not relieve the burden of reproducing the last one to two octaves. The passive attenuation circuit does that by filtering these low frequencies so that they never reach the main speakers. That way, the mains can concentrate on the easier-to-reproduce signals above 80Hz or so.

If you use high-pass in sub, it will take take pressure off your mains.

Best if you do this with stereo subs.