What to do when ive got too much cubic feet of box space for subs?

[Mike Hawk]

Ive got two JL 10w1v2 subs which require 0.625 cubic feet for a sealed box. My sealed box has 1.0 of cubic feet for each sub chamber of the box. Now i know poly fill makes subs think they are in a bigger box but what can i put in the box to make the subs think they are in a smaller box? Or do i even need anything, just leave each chamber empty?

[LETHALxLS1]

I would see how it sounds before I did anything. If it sounds like doo doo-which I doubt, try some spray foam insulation-they sell it at wal* mart.

[fredmr85]

bracing never hurts