box for 2 18'' ssa xcons

[synyster 0]

im building my third box but first wall and i always wonderd if when i calculate the cubic feet of the box do i subtract the port cubic feet??? i have come up with a box thats 17.5cf but the port is 2.4cf and each woofer is .25cf so its like 14.6cf .please some one correct me if im wrong im not to sure

[synyster 0]

Please someone help!!!!

[Aaron Clinton 2,372]

Yes, you want to know after port displacement.

[synyster 0]

Yes, you want to know after port displacement.

Well that means I gotta re calculatethe port after the new dispacement