to say the sub will take .5 cubes away from the box is nuts! I have an RE XXX 15d2. The sub mounts into the box with a height taller than a 2 Liter bottle of coke. Even with a sub that is taller by 2 inches than a 2L bottle of coke with a monster of a basket it only takes up .27 cubes of disp. In fact the only sub I know of that has that kind of disp. is the 22 inch sub from Atomic, and the MTX jackhammer. the 22 or 24 i forget now lol. half a cube of disp is alot of space for a subs motor and basket to take up.