I'd go with what ID says. They seem to know what they are doing and I would trust their recommendations. I have two IDQ 10's that I have in a sealed box built according to ID's specs. These speakers are very musical, they sound great. I suppose if you have extra time and materials, building a couple of boxes would be nice to compare, but personally from how my subs sound, I'd save yourself the trouble and build the box to their specs.