I'm curious, i'll have to double check with Kicker now.:scratch:That still sounds a lot. It really doesnt matter what system you work to, as long as you get the figures right. I simply work in litres and know the standard normal volume taken up by most drivers, when I convert that in cu ft, it comes to about 0.1-.02 cu ft, so 0.5 seems unusually high. If thats the figure they have given you though, it must be correct, it just sound a lot IME. My drivers are quite large and I was given a figure of 3 - 4 litres for that one.