sub box subwoofer ported vented vent port rockfordfosgate custom large boom bass jl jlaudio

Weighing in at 3.45 cu ft volume the port is tuned at 37Hz. L=24" W=20" H=12". Almost the golden ratio, but I didn't have enough room in my trunk for a 32" length. I am replacing the speaker with a JL 12W3V2.