I was told 1 sub for each 10,000 cubic feet. With an 8 foot ceiling you'd be close to 20,00o cubic feet. So yes.
Do I really need a second 2Wq sub?
My listening room is 12x by 20x and my system is on the short wall. I have the Vandersteen 3A sigs, my audio rack and one 2Wq sub on that wall. The one sub really improved the sigs and the sound overall. I can sqeeze in a second sub, but I'm wondering if a second sub in that size room would be unnecessary overkill. I'd like hear your comments.