Maybe email one of these guys, ask them what box sizes work well: http://forum.sounddomain.com/forum/u...=070136#000000

 

well as it stands, the boxes are 1.6cubic feet each... and what is qtc?

 

Qtc is the total Q of the speaker in an enclosure including all system resistances. A Qtc of .707 is the most common and generally produces the flattest frequency response with approximately a 6dB/octave rolloff. Higher values of Qtc will give a peak in the output with a sharper rolloff. A lower Qtc will start to roll off earlier and will roll off at a slower rate. If you don't know what Qtc you need, start with a Qtc of .707.

Taken from here: http://www.bcae1.com/spboxad2.htm