Hi! I am currently building a 1.685ft3 sub box with a center divider and I was wondering how much polyfill I should add into my box. The spec sheet calls for the box being lined w/ 1in. thick of polyfill but I have heard from other people that I should loosely stuff in 1/3 of each box's worth. Then I went to this website ( http://www.eatel.net/~amptech/elecdisc/ ) that said:

Poly-fill can be used to make an enclosure seem slightly larger. It does this by slowing the movement of the air in the enclosure. This, in effect, smoothes the frequency response of the subwoofer's output and slightly improves its low frequency extension. This image shows, to what degree, it does both. The red line (no fill) has a slightly higher peak than the yellow line before it starts to roll off. The yellow line has a slightly improved low frequency extension when compared to the red line. The effect is not very dramatic but using poly-fill in this manner can sometimes make a subwoofer sound better. The red curve is has no poly-fill. The yellow line is 100% filled with poly-fill. 100% fill is equal to 1 pound of poly-fill per cubic foot of air space.

1.68 lbs of polyfill would be a buttload! So what do I do? Thanx A Bunch!

dunno but from experience we used it in a 1cu ft box for a 10in kicker solo baric per the instructions, and at a later date removed it to see if there was a difference, and we noticed none. Just my 2 cents

I usually fill about half the enclosure with polyfil...