is this right

[suckerfreebass]

a buddy designed a box for my lvl 4 18 with xl soft parts an he came up with 24 depth 24 height 40 width port 22.5 height width 6 and length 28 tuned to 32.83 is this right an is this box gonna be to big for the sub im pushing 1500 rms to it an dc recommends

6 cubes