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