I've got a 19' x 28' room in the basement of my house and there are no problems. I insulated (r-13) around the perimeter and ceiling to "deaden" the audio a bit, but nothing special beyond that. (Since you are in Canada, you might consider using flannel instead ).

A sub is the only thing that should provide any challenge. It is INCREDIBLY difficult to contain robust LFE. My HSU VTF-3 HO just pummels the china cabinet upstairs in the dining room, even with the insulation.

As an aside, pretty much all of my friends have their HT in the basement.

Good luck with it - you will enjoy the end result.