is a cubic foot a cubic foot inside a box?

Dimensions : W - 20", H - 15", D - 9.5"

dimensions: 29-7/16"W x 14-3/8"H x 8-13/16"D1 x 5-1/2"D2


would those differences matter in a sub or not as long as it ends up being 1 cubic foot correct?


elemental design is the first one....they are built to order though....$125

the 2nd is a Q-logic box...$89