JL's recommended enclosure volumes are spot on.
1.25 ft^3 + .1 ft^3 (sub displacement) = 1.35 ft^3 sealed //content.invisioncic.com/y282845/emoticons/yumyum.gif.0556df42231b304b9c995aefd13928a8.gif
I've tried:
1 ft^3 (tight/punchy, little bottom end)
1.75 ft^3 (loose/boomy, little top end)
2 ft^3 @ 32 Hz (moved more air, but SQ took a big hit)
For my next box I'd like to see how it does in 1.5 ft^3 @ 28 Hz