michael chuaMay 4, 2018Car Subwoofers18", Car Subwoofers, PW1870, Pyramid, Vintage Pyramid PW1870-US Thiele & Small Parameters Recommended for In-Car Use Ported Box 20cuft. F3=29Hz Recommended for In-Car Use Sealed Box 8cuft. F3=42Hz Sealed Box 15cuft. F3=37Hz, Q=1.07 Sealed Box 25cuft. F3=34Hz, Q=0.93 Sealed Box 35cuft. F3=33Hz, Q=0.87 Sealed Box 50cuft. F3=32Hz, Q=0.82 Sealed Box 72cuft. F3=32Hz, Q=0.78 Sealed Box 100cuft. F3=32Hz, Q=0.75 Sealed Box 200cuft. F3=32Hz, Q=0.72 Sealed Box 300cuft. F3=32Hz, Q=0.71