Digital Room Correction (like TacT) is probably your best solution. I use the Velodyne SMS-1 with subs which applies DRC only to the bass region, but I'm not sure it'll fix what's ailing you up there in the mid bass. Audyssey makes a full range DRC system that's pretty commonly included in HT receivers and (less often in) pre-pros, as well as in a (rather expensive) stand alone unit. Also expensive is Meridian's version which works from IIRC 300hz down.
Good Luck
Marty
PS, beware fullrange loudspeakers (and subwoofers) in NYC, as IME the neighbors may not be pleased!
Good Luck
Marty
PS, beware fullrange loudspeakers (and subwoofers) in NYC, as IME the neighbors may not be pleased!