I made a fiberglass sub box that goes in the rear most corner of my trunk on the passenger side. My rough calculations said it'd give me ~.6 cft. Due to conflicts with my tail light covers, I had to revise the box design and now that it's done, the thing has exactly .47 cft. The rep from Crystal said I need a box that's .54- .66 cft sealed for my sub to be most efficient.

As far as I know, adding some polyfill is the only way to make the box "bigger" (I use that term loosely, because I know it's really only tricking the sub.)

So my question is this, how much polyfill should I add? Should I even bother adding some?

Is there even any measurable way to add polyfill to get a desired ~.10 cft effect from it?

What would you guys suggest I do?

 

usually you would loosely fill it half way, so more than half, it wont hurt it to fill it up.