Study this guy's site for awhile. You need to eq to compensate for the low frequency losses, so you need lots of good quality displacement. In return you get freedom from many of the room modes that play havoc with your system's bass in the time domain.
http://www.linkwitzlab.com/design_of_loudspeakers.htm
http://www.linkwitzlab.com/design_of_loudspeakers.htm