I'm currently comparing Velodyne HGS II 10" vs 12" and maybe the 15". But for main comparison, is the difference between the 10 and the 12 significant if my primary use is 2-channel music (75%). Room is 13x20x7.5=1950 (with 2 openings into another room). Although I wouldn't classify myself as a bass fanatic, my speakers go down to 40hz so I'd like to fill in the bottom end but I won't be trying to shake the house. So, the price difference isn't a factor but I'd like to get away with the smallest box possible.