I'm building two boxes for two different subwoofers and I have various questions about both types of enclosures(ported and sealed). I need some advice from one of you tech guys (zane?).
The enclosure I'm building is to house a 12" sub that needs 1.5 cubic feet of airspace. The dimensions of the box I've come up with to both serve my purpose and enclose the woofer are 13" H, 42" W, 3" D1(top), 7" D2(bottom). Do these outer diminsions give me 1.5 cubic feet (or close to) using 3/4" particle board? What is the formula you use to calculate this?
Also, would stuffing this box with poly-fill make the sub sound better? If not, should I just pad the inside?
The ported enclosure is to house a sub that requires 1.4 cuft of air space. The port is 3" H x 18.5" W. If the length of the inner chamber is 16.8" deep, how deep should the port be to tune the box to 30hz? What is the formula you use to calculate this?
Finally, I'd like to know the name of a good freeware or shareware program for CAD of boxes.