It features a non-resonant cone and dust cap structure, dynamic linear suspension, SD-1 magnet system, "Grasshopper" cast chassis with maximized air flow and resonance terminating mounting system. Less resonance in all structures, lower compression and higher linearity, faster termination of excess energy and higher sound pressure capability. The 18W/4531G should have an F3 of about 65Hz sealed and 40Hz vented. Also an excellent choice for high end autosound applications.
Outside diameter: 182mm
Cut out: 156mm
25.4mm = 1" = 2.54cm
Also written as: 18W/4531G-00, 18W4531G00, 18W 4531G 00, 18W 4531G00, 18W4531 G00
0.3 to 0.4 cubic foot sealed with 20% filling for and F3 of 78Hz
0.7 cubic foot box with 2" vent by 7" long for F3 of 45Hz
1.0 cubic foot box with 2" vent by 5" long for F3 of 40Hz
The Sealed alignment will go lower in a car with the car's cabin gain.