Which subs are best for home theater?


I now have a double 12" self-powered sub that I'm using in the front channel for home theater. I am thinking of adding a rear-channel subwoofer. My dealer has suggested using a single 15" down firing sub in both front and rear channels. Would a 15" in the rear be overkill? Should I use a 15" for the front? And maybe use the double 12" sub for the rear channels?

Another question would be is a double 12" sub better on audio than the single 15" sub?

Thank you in advance for your suggestions.

MR.upgrade
mrupgrade
I definately think the Talon Roc gives the best of both worlds for home theatre and music. It has the speed of the Velodyne and the integration of the Rel. I really like it with my Martin Logan set-up.
I hadn't breakfast today and I'm waiting to get some Pizza Hut meatball supreme sub now.
i have tryed the servo 15 and also definiteve sub
but as for now i have velodyne hgs 15" witch is the best one ever had.
you can fill the air moving around and the exsplotion are real to life.
try the velodyne hgs-15/18 you cant go worng with them.
haim.
Marakanetz, does that accomplish the job of getting the air moving?

Do you find it difficult to integrate with the main course? Which direction does the main pressure come from, front or downward?

Hope these questions are not too technical.
albert: good questions. and i will add my own: are you, marakanetz, as i assume, also retromingent? -cfb