Some more information about your room and speaker placement might be very helpful. Loft is really cool, but really bad for the acoustics, have one so can appreciate it. Doomsday prediction: It is possible that you never will be able to have the same imaging from L and R if they are not placed ideally, even with the best of EQ. More rosy prediction: You might have to do a whole lot including placing your speakers differently aka rearranging the loft and use some EQ that might help.