just build the box that's in the manual if you don't know what you're doing....
i went half way between the two enclosures and had a 33hz 4.5 cube enclosure.
tuning got a bit messed up and was ~35hz, but it still sounded alright.
i tried tuning high @ 42hz, too, but threw that box in the fire after about an hour.
30-55hz is the best freq. range for the 15's.
they can't go high like the 12's, so tune low, and take advantage of the big cone
and by they can't go high, i mean that they can physically play up to 80hz or higher, but imo they sound like complete ***, and don't have much output
