ok, the port does NOT count for the subs 'wanted' volume.
so if i wanted a RE SE 10" subwoofer (i have one

) and RE says "it likes 1.2cubes ported".
it needs 1.2 cubic feet behind it. the sub displaces lets say .2cubes (for ease). now i need my box to compensate for the area that the sub takes up, so it now needs to be 1.4 cubes. so now i have my box size. 1.4 cubes (after sub displacement)... so i go to the port calculation and i say, lets do 1.75 wide, but 11 tall, gotta be about 34" long (made up). that is gonna take up .37 cubes not including the wall of the port (lets say .75" thick, 3\4 MDF) and there is no bend in the port...that piece of wood takes .16cubes itself. so the gross port volume (inside the box) will be .53... so we need to make a box that is 1.4+.53. that would be 1.93 cubes for the entire box... and thats internal.
port does NOT include inner volume. the inner volume must be what is recommended for the sub, and the port should be added to this for the GROSS volume. everything that goes into the box must be taken into account so it stays at the required volume.
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