E-12 V.3 D4 - Sundown Audio 12" 500W RMS Dual 4-Ohm EV.3 Series Subwoofer RMS Power = 500-watts | Xmax = 14mm one-way by 70% BL | Vented magnetic gap Vented pole piece with optimized geometry | Black Aluminum 2.5 voice coil former for superior heat dissipation | High Temperature 4-Layer copper voice coil wire Spring Loaded Terminals | Stitched-On Mini-XL Tinsel Leads to prevent fatigue and failure Specifications: DC Resistance (Re): 6.1  | Resonance Frequency (Fs): 36.6 Hz | Equivalent Volume (Vas): 30.8 L | Electrical Q Factor (Qes): 0.53 | Mechanical Q Factor (Qms): 4.58 | Total Q Factor (Qts): 0.47 | Force Factor (BL): 24.4 NA | Moving Mass (incl. Air Load) (Mms): 224.0 g | Suspension Compliance (Cms): 0.08 mm/N | Sensitivity: 86.4 dB 1w / 1m Box Recommendations: Sealed: 1.0 ft^3 | Ported: 1.75 ft^3 | Displacement: 0.12 ft^3 | Depth: 6 1/2" | Outside Diameter: 12 1/4" | Cut-Out: 11 1/8" | Recommended Tuning: 32hz | Recommended Port Area: 28 in^2