SB ACOUSTICS SB42FHCL75-6, 42cm PAPER FIBER CONE SUBWOOFER 6OHMFeatures Light weight rigid honeycomb cone (hard paper honeycomb with fiber glass skin layers) 3″ copper voice coil for improved power handling Long life silver lead wires Vented pole piece for minimum compression Vented cast aluminum chassis for optimum strength and low compression Low damping rubber surround for improved dynamic linearity Non-conducting fiber glass voice coil former for minimum damping Large motor system Specs Nominal Impedance 6 Ω DC resistance, Re 4.6 Ω Voice coil inductance, Le 2.1 mH Effective piston area, Sd 850 cm2 Voice coil diameter 75.6 mm Voice coil height 31 mm Air gap height 8 mm Linear coil travel (p-p) 23 mm Magnetic flux density 1.1 T Magnet weight 3.6 kg Net weight 10.2 kg Free air resonance, Fs 18.4 Hz Sensitivity (2.83V/1m) 93 dB Mechanical Q-factor, Qms 7.4 Electrical Q-factor, Qes 0.32 Total Q-factor, Qts 0.31 Moving mass incl. air,Mms 166 g Force factor, Bl 16.7 Tm Equivalent volume, Vas 462 liters Compliance, Cms 0.45 mm/N Mechanical loss, Rms 2.6 kg/s Rated power handling* 300 W * IEC 268-5, T/S parameters measured on drive units that are broken in.