I've got a box right now (a custom built truck box) for two 10"s that's sitting at .95 cubes per sub after sub and port displacement. I need to get this number up a little closer to 1.3-1.5 cubes, and the only way I can think to do this is by using polyfil, as I have the dimensions as big as they'll go. Now, since this is a ported box, I need to know **** near the exact Vb of the box in order to properly tune it.
My question is, how do I know how much exactly polyfil will add to my box; or, more specifically, how much polyfil to add to gain half a cubic foot of volume.
Or, any other alternatives to making the box bigger? The ports are already partially external.