Recommended for professional audio and bass in a vented enclosure, the Eminence Kappalite 3015 LF PA speaker has a power rating of 450W and a peak of 900W.Specs: Nominal basket diameter: 15", 381mm Nominal impedance: 8 ohms Power rating Watts: 450W Music program: 900W Resonance: 42Hz Usable frequency range:: 40Hz-1.5kHz Sensitivity: 99.8 Magnet weight: 11oz. Gap height: 0.365", 9.27mm Voice coil diameter: 3", 76.2mm Thiele & Small Parameters Resonant frequency (fs): 42Hz DC resistance (Re): 5.31 Coil inductance (Le): 0.92mH Mechanical Q (Qms): 6.82 Electromagnetic Q (Qes): 0.41 Total Q (Qts): 0.39 Compliance equivalent volume (Vas): 158.8 liters / 5.6 cu.ft. Peak diaphragm displacement volume (Vd): 846cc Mechanical compliance of suspension (Cms): 0.14mm/N BL product (BL): 18.6 T-M Diaphram mass inc. airload (Mms): 101g Efficiency bandwidth product (EBP): 102 Maximum linear excursion (Xmax): 9.6mm Surface area of cone (Sd): 881.1 cm2 Maximum mechanical limit (Xlim): 17.0mm Mounting Information: Vented enclosure: 102-193 liters/3.6-6.8 cu.ft. Overall diameter: 15.32", 389.1mm Baffle hole diameter: 14.03", 356.4mm Front sealing gasket: fitted as standard Rear sealing gasket: fitted as standard Mounting holes diameter: 0.28", 7mm Mounting holes B.C. D.: 14.56", 369.8mm Depth: 7.25", 184.2mm Net Weight: 8.6lb., 3.9kg Materials of Construction Coil construction: Copper voice coil Coil former: Polyimide former Magnet composition: Neodymium magnet Core details: Vented core Basket materials: Die-cast aluminum basket/heatsink Cone composition: Paper Cone Cone edge composition: Cloth cone edge Dustcap composition: Solid composition paper dust cap