I've recently started replacing my 10 year old 5.1 setup.  So far I've got a 5C and two 6T's (via an Onkyo 805) both of which blow my mind.  Now my sub is terribly out classed and I need advice on choosing between the 10/12D subs.  Some background:  listening area is 20x14 (L/R, center and sub on long wall) with another 20 ft. of open area to the left.  60/40 on movie/music listening.  I love rock/metal at 110dB+ (got the 6T's at 114dB yesterday!) and I need a sub that will keep up with loud yet musical bass.  Movies are mostly action with the need for deep 'dinos in my room' bass.  I was initially thinking 10D since my listening area is not huge.  But I'm worried the 10D won't provide the headroom I might need when I'm trying to melt my face...thoughts?