Hello?
Speaker Enclosure Volume Calculator
The calculator(s) there says this about your speaker:
- This speaker is better suited for SEALED enclosures.
- Total box volume 1.5 cubic feet. For a plain rectangular box that would measure 12"x12"x18" (HxWxD) and that's the measurements of the INSIDE of the box.
There's also a calculator there if you want to make boxes with an angled face.