box question

[christamez80]

ok so im building a box for 4-18's Obsidian Audio and the box is 25.28 cu ft internal. subs are 0.25 cu ft displacement. question is on the port calculator do i put net internal volume or after sub displacemnet volume to figure out the tunin for the box? im using the calculator on carstereo.com, cant download torres calculator for some reason. subs are 20mm xmax just in case anyone needs to know. thanks ahead of time if anyone can help

[Thespeakershoppe]

After displacements. Displacement eats up air space. In you case around 1 cube. But with a 28 cubic fit box won't make too much of a difference

[christamez80]

I appreciate the help. This is my second box to build. First one I tuned it before displacement and it sound good but since this is a bigger build I want it correct.