The title says it all really. I've got my two Coustic HT-812's in a dual chambered, ported box. Each chamber is 1.3 cubes with an 18" long 4" wide port tuned to about 35ish Hz. Now I know that polyfill makes the sub behave as if it were in a larger box. What I would like to know is how that would affect the tuning of the box. I'm presuming it would lower the tuning frequency, although I'm not too sure how much of a difference it would make. Any thoughts?