Here are my two new Ultra 12's, I sold my ULS-15 to get a sub with a smaller footprint, but with the price of these I just had to get two.
I have to say that I am not dissapointed in the least with my decision. Im not very technical and I do not own an SPL meter
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But I do trust my ears and in the end what matters most is what sounds best to the person.
In direct compairison to my ULS I have to say that at least in my small room these Ultra's have more impact for home theater, most likely because they seem to be alot stronger in the midbass. Also they are both corner loaded which the ULS was about 1/4 of the way in from the front wall next to my TV.
The fact that you can get a quad drive of the Ultra 12's for about the same price as one ULS-15, says to me this is a great deal and if you're thinking about getting one you will not regret it.