OK i got the box bluprints from RE( for 15" x.x.x.) 1 was for a 5 cube box with port tunning of 23Hz-one was for a 4 cube box with port tune of 36Hz and 1 was for a 6 cube box wich is too big for me.you guys (glass, i think) , however, recomended a 4 cube box with a port tune of 27 Hz to wipe out a 13w7. how do i go about making the 4 cube box with a port tune of 27 Hz ?? i got the hifonics 1500 by the way ,recomended. oh and the sub is dual 4 ohm.