A sub suspened in the middle of a room = spherical dispersion would be flat or 0
on the ground = hemishere or 1/2 sphere
on the ground against a wall = 1/4 sphere
on the ground, against a wall in the corner 1/8 sphere.
any placement to reduce the radiation pattern should increase perceived output.
Also, the driver is on a plane most of the time in a door in a mostly IB setup. If you make an enclosure for the driver that would help too.