box help

[magicman 0]

i made a box using RE box builder and this is what i cam up with i am putting a 18" night shade in it how much air space do i have and whats it tuned at i think iKnow but wanna double check with you guys first

W=36

H= 22

TD= 24

Bd= 24

1"MDF

port 1= 6"

port 2= 4"

[mikee72 0]

with the p1 and p2 are you talking about the port width?