Thanks for all of the advice guys. Well..against the grain of some of the advice here, I went with the Seismic 12. I found a local dealer that carries both the Seismic 12 and the DD12. I auditioned them side by side and calibrated to the same level. At first, I thought the Velo was punchier and had more impact, but after extended listening, the Seismic sounded much more natural to me for music. Once I upped the volume level on home theater, the Seismic actually was the sub with more impact.
I do need a small sub, and my room is relatively large, so for me, the Siesmic had the least amount of compromises. I will let you guys know once I get it in my room.
Thanks again
Greg