IMPERO-15C Professional Serie High power driver recommended for pro audio in vented enclosures. Suited for two-way top boxes, full-range two-way and three-way boxes, bass guitar boxes, and small subwoofers. 4 ohm. SPECIFICATION Nominal Basket Diameter 15", 381 mm Nominal Impedance 4 ohms Power Rating Watts 1200 W / Music Program 2400 W Resonance 40.27 Hz Usable Frequency Range 50 Hz - 2 kHz Sensitivity 93.5 dB Magnet Weight 109 oz Gap Height 0.5", 12.7 mm Voice Coil Diameter 4", 101.6 mm THIELE & Small Parameters Resonant Frequency (fs) 40.27 Hz DC Resistance (Re) 3.11 Coil Inductance (Le) 1.08 mH Mechanical Q (Qms) 10.96 Electromagnetic Q (Qes) 0.34 Total Q (Qts) 0.33 Compliance Equivalent Volume (Vas) 122.15 liters / 4.31 cu.ft. Peak Diaphragm Displacement Volume 634.7 cc Mechanical Compliance of Suspension 0.12 mm/N BL Product (BL) 17.4 T-M Diaphragm Mass inc. Airload (Mms) 131.03 grams Efficiency Bandwidth Product (EBP) 118.3 Maximum Linear Excursion (Xmax) 7.41 mm Surface Area of Cone (Sd) 856.3 cm² Maximum Mechanical Limit (Xlim) 15.4 mm MOUNTING Information Recommended Enclosure Volume Sealed N/A Vented 53.8-118.9 liters/1.9-4.2 cu.ft. Overall Diameter 15.22", 386.59 mm Baffle Hole Diameter 13.99", 355.35 mm Front Sealing Gasket fitted as standard Rear Sealing Gasket fitted as standard Mounting Holes Diameter 0.28", 7.24 mm Mounting Holes B.C.D. 14.56", 369.9 mm <