Below is what someone posted on avreview site about the PB12-ISD,you are talking about the PB12+2(which is 2 plus drivers rather than 1 I driver)there should be no contest.Also how much are you paying for the REL? against smurfins sub.
This is actually an updated review for the PB2-ISD subwoofer that I received and reviewed approximately one-week ago. Please again note that I am reviewing (re-reviewing) the PB2-ISD subwoofer here as there is no separate section in Audio Review for an evaluation of this specific model of subwoofer.
After having used the subwoofer for about a week, and learning more about its operation, I think that more and more it is an excellent value for the money.
I have revisited and relistened to some of the other subwoofers that I was considering purchasing such as the REL Strata(??)and Stadium III's, B&W ASW 750, Velomax 1200, Klipsch RSW's (all woofer sizes), etc. and find that this subwoofer is at least as good, if not better, than most of the aforementioned subs, except for the $3,000.00 REL Stadium III. (The REL Stadium III is not any more dynamic or powerful, but does have a bit tighter, cleaner and faster bass response than does the SVS. However, again, the REL Stadium III is a $3k subwoofer so this is not really an appropriate comparison.) Other than the REL Stadium III, these other subwoofers were no more pleasing to the ear or more effective in producing bass levels than was the SVS. In some cases, these more expensive subwoofers were a bit weak, in my humble opinion.
The SVS remains a very powerful bass producing sub. The bass easily can shake a room and goes reasonably low enough to capture almost all of the low bass sound tracks that exists on DVD, etc.
When I first set up the subwoofer, it had a tendency to get "boomy" with bass heavy movie DVD soundtracks. Fortunately, I have been able to largely (but not quite completely)cure this tendency by moving the subwoofer more towards the side of the room (away from the corner), and to reduce the gain/volume somewhat when playing bass heavy movies/HT DVD's. By the way, even with the reduction in gain/volume, the reduced subwoofer setting still allows for plenty of bass production and will result in ample room shake, etc. when called upon to do so.
Also, it should be clearly noted that the customer service recently received from Tom V of SVS Subwoofers when dealing with the boominess issue has been absolutely first rate. Tom has promptly and comprehensively responded to all of my inquiries in a largely successful effort to reduce the boominess issue. I greatly appreciate this high level of customer service. It should be a good lesson for us all.
All in all, I believe that the PB2-ISD subwoofer is a terrific value for the money. Is it the best subwoofer out there? No. However, I have listened to a number of subwoofers and have discovered that I would have to pay at least $3k to exceed the quality of this subwoofer. Moreover, I suspect that there are other $3k subwoofers out there that are not as good as the SVS.
My advice is, buy the SVS now while you can you won't regret .it