Well, I got the MB Quart after all and have been testing it out for the last couple of weeks. After having two SVS ISD driver-based subs, I can say the MB Quart is a far more musical, very tight sounding, easy to integrate subwoofer, almost like picking up a REL subwoofer for a much lower cost. It won't shake the foundations of a house, but its bass is much more controlled, and it still has plenty of impact for movies. Sound effects are much better defined and seem to hit more sharply. SVS does the impressive house shaking, room pressurizing thing very well though.
The design of the MB Quart is one downfiring active driver, with two passive drivers angled at 45 degrees to the front. Shipping weight was 135 lbs, so actual weight on the unit is a little over 100 lbs. The cabinet surround is real joined wood, very solid high-end construction throughout with an XLR input and remote volume control to boot. I've paired the subwoofer with a pair of LSi9's now with extremely good results, so good that I decided to remove a pair of SDA-1Cs from the front of my theater system. The MB Quart is a keeper.
