I know this has probably been discussed here before; but I need some help with building a subwoofer box. Currently I have a JL 13w1v2 subwoofer in a store- bought sealed box. The bass it puts out is pretty good for a low power sub, but I'm looking to be able to hit some lower frequencies. I know the basics from doing some research on the net. Using 5/8-1'' MDF, bracing, how to seal the box etc., but I having trouble understanding how to actually port the box and to how large the box, and port would have to be. Below are the specs of my subwoofer: Free Air Resonance (Fs): 20.9 Electrical “Q” (Qes): 0.4060 Mechanical “Q” (Qms): 6.9366 Total Speaker “Q” (Qts): 0.3840 Equivalent Compliance (Vas): 6.131 cu. ft. / 173.51 liters One-Way, Linear Excursion (Xmax)*: 0.475 in. / 12.1 mm Reference Efficiency (no): 0.375% Efficiency (1W/1m)**: 87.71 dB SPL Effective Piston Area (Sd): 105.774 sq. in. / 0.0682 sq. m. DC Resistance (Re): 4.114 ohm Nominal Impedance (Znom): 4 ohm Thermal Power Handling (Pt): 200W Driver Displacement: 0.05 cu. ft. / 1.42 liters Net Weight: 11.21 lbs. / 5.08 kg Here is also a link to the JL website if you would need more info.: JL Audio Products: Subwoofers / 13W1v2 The car this is going into is a 2001 Chevrolet Monte Carlo if that gives you any idea of the trunk space I have. TIA for all replies.