While I cannot comment directly on the DD series, I can on the predecesor, the HGS. I have the HGS 10 and it is one of the best subs I have ever heard, period. It plays tremendously deep for a 10 and is very musical and dynamic. The DD series woofers utilize an upgraded servo and a built in room eq with a separate microphone to balace in room response. I saw a review somewhere on the DD 12 and it was nothing short of glowing. Also, I believe the DD series start around $1999.99.
