This is going to be a different kind of suggestion, but, hey, I seem to go against the grain.
Despite the "conventional wisdom" that you NEVER stuff a ported box, I find it does away with most, if not all, of that boxy sound a ported speaker can exhibit. I was told this by a well known speaker guru, whose unorthodox ways provide a tremendous amount of speaker improvement at such little cost, it's laughable. His recipe, pick up some polyester batting from a discount store (fabric, KMart, WalMart, etc.). Tear off medium sized handfuls, not too tight, and loosely throw them into the box. Fill it up about 75%, remembering that too loosely is preferable to packing it too tightly. You can facilitate this by removing the woofer from the speaker, then putting it back after your finished. No need to disconnect the driver.
And, if it sounds totally crazy, just remember that Bud Fried's Line Tunnel and what Von Schweikerts calls their "transmission line" is nothing more than a ported speaker, stuffed with foam. Neither of which produce boxy, boomy bass.