After reading this forum for 9 months I decided to go wth a ULS-15 Dual Drive system. Here is the reason I picked the ULS-15s. I wanted a powerful subwoofer (1000 watt) with super low extension (10 HZ) in a premium finish (Walnut) to be placed inside a family room which is open to everything on the first floor (8000 cubic or more). My listening habits are 50% HT/ 50% Music so I was leaning towards a sealed sub.
Since I already own a Velodyne HGS-12 and a VA-1012, my midbass in room response was great. While I was waiting on the Hsu's to arrive I even thought "Why do I need any more wooferage?"



Well after setting them up and dialing them in, which took almost three weekends, you all know, place one here then move one there then swap this one with that one and so on I put the normal demo material on. TDK, Ironman, Incredible Hulk and others. All I can say is the same as Robin in Batman and Robin:
"Holy (insert), Batman!" 

. The Ironhide flip in Transformers was grinning provoking.

I have never experience the full spectrum of bass like that before. The sound cannons in Incredible Hulk chased away all of the wildlife in the back yard.

JK but it was easy for the Hsu's to play the 10 hz information in that scene. I also now believe that I am in the cave with Ironman. Along with watching David Gilmore live at the Royal Albert Hall and the Eagle's Farewell tour from Melborn my collection of video concerts including the ones played on the MTV HD channel Paladium never sounded better.
All of the demos i have shown to friends and neighbors all commented the same way. They proclaimed "That's the cleanest bass I have ever heard."
Also. I can't believe some of you that actually bought the Quad drives. But I guess in my own way I am using four subs so I guess I understand. I could get by with just the two Hsu's, since they are quite powerful even when the gain is only set at 10:00.
So if you all are looking for outstanding cabinet workmanship in a well rounded 15" powerful subwoofer you too might want to check out the ULS-15s.
See signature for location of pics. One is by the couch and one is in between our recliners.
Peace