X-12 V.2 D4 - Sundown Audio 12" 1500W RMS Dual 4-Ohm X V.2 Series Subwoofer X-12 V.2 D4 - Sundown Audio 12" 1500W RMS Dual 4-Ohm X V.2 Series Subwoofer Specifications: DC Resistance (Re): 6.1  | Resonance Frequency (Fs): 38.3 Hz | Equivalent Volume (Vas): 13.2 L | Electrical Q Factor (Qes): 0.50 | Mechanical Q Factor (Qms): 4.92 | Total Q Factor (Qts): 0.45 | Voice Coil Inductance (Le): 3.82 mH | Force Factor (BL): 30.0 NA | Moving Mass (incl. Air Load) (Mms): 305.6 g | Suspension Compliance (Cms): 0.06 mm/N | Sensitivity: 84.4 dB 1w / 1m Box Recommendations: Sealed Enclosure Suggestion: Not Recommended | Ported Enclosure Suggestion: 2.50 cu. ft. | Displacement: 0.20 cu. ft. | Depth: 9.67 in | Outside Diameter: 12.68 in | Cutout: 11.09 in | Recommended Tuning: 32 Hz | Recommended Port Area: 40 sq. in.