Woofers work well in a range of cabinet volumes. For example, I'd expect the woofer you've described to work very well in cabinets from 0.5ft3 to 2.0ft3 tuned to 25-30Hz. If you're going for a full-range speaker with a wide-bandwidth woofer, something like a small two-way speaker, then I'd go with the PiAlign suggestion. But if you are going for a sub, I'd look at alignments that use larger cabinets to get deeper response.