I'm told to go with a ported enclosure, you'll benefit from a subsonic filter.
This is probably a dumb question, but ebay turns up this, a passive adjustable subsonic filter. However, all the frequencies are a multiple of five. Would I have to port the box to the same frequency, or would a Xhz enclosure and X-4hz subsonic filter work fine?
EDIT: Just to make myself sound more like an idiot: this thread answered this, but I have no idea what a 1/2 octave would be.