> ...a 5 cu ft box is rather large, is there any way > you can modify it to take 2 SVC 12" ? When you > double the cone area, you make the system 3db more > efficient.
I don't agree.
With 2 12 inch SVC subs, each with 2.5 cu.ft and getting just 50 watts wach, their X-max would probably not be reached !
A 12 inch sub (or bigger) with big VAS would be glad with this big box and would be very much efficient. Doubled VAS -=> +3dB gain in efficiency