How much Net airspace should a 15" BTL see total?

[Carnivorous18]

Ill be trading in the 18 for a 15 and I need to know how much airspace after all displacements the sub should see to be efficient. It'll be running on 3K watts if that makes a difference

[Carnivorous18]

Bump

[RAM_Designs]

3-3.5ft^3 if you plan on using 3kw.

[galacticmonkey]

Yeah, shoot for 3.5 cubes.

[Carnivorous18]

Cool ill shoot for 3.5 then. Thanks guys