I currently have Paradigm studio 40's as fronts, 20's for surround and CC center speaker powered by Denon 3801. I listen to alot of acoustic rock, thru harder rock with a growing interest in Jazz and Classical. I'm up in the air as to which sub would best fit my needs. I'm in a small room (14' wd x 16' lg x about 10' high). I seem to enjoy 2 channel listening to multichannel or home theater. They are both known to be quick subs capable of reproducing music. The NHT is +- 3db down to 21 hz, the ACI +-3db to 20 hz but i'm sure the NHT might be slightly louder overall. Thanks for your inputs.