external port

[franklucas]

If I have 4 inches of external slot port out of 30 totAL inches of port length do those 4 inches of port count towards my port are per ft3 box volume ratio? Thanks

[Joe X]

No it wouldn't since it's port area/ net volume, you would need to factor in the lost port displacement for the part being out, that said, you should not calculate port area based on the port area/cube rule specially if you are working with a non average sub.

[franklucas]

Thanks Joe X I have 2 dc lvl 6 18s and found a port area formula that uses xmax as a guidline. The formula says I need 316 inches of port area so a 17.75 X 17.75 port size is what I need to start with? Thanks man