SB ACOUSTICS SATORI WO24P-4, 24cm PAPYRUS CONE NEODYMIUM WOOFER BLACK 4OHMFeatures Hard paper cone for improved piston operation (made in-house) Large optimized motor system with under-cut pole piece and dual shorting rings Vented aerodynamic cast aluminium chassis for optimum strength and low compression Soft low damping rubber surround for optimum transient response Linear symmetric suspension design for improved dynamic performance Non-conducting fibre glass voice coil former for minimum damping Long life silver lead wires attached 180° apart for improved stability Vented pole piece for reduced compression High piston to chassis diameter ratio Gasket and bolt hole protrusions for reduced coupling to speaker cabinet Specs Nominal Impedance 4 Ω DC resistance, Re 3.3 Ω Voice coil inductance, Le 0.29 mH Effective piston area, Sd 255 cm2 Voice coil diameter 49.5 mm Voice coil height 23 mm Air gap height 6 mm Linear coil travel (p-p) 17 mm Magnetic flux density 1.1 T Magnet weight 1.36 kg Net weight 3.7 kg Free air resonance, Fs 28 Hz Sensitivity (2.83V/1m) 91 dB Mechanical Q-factor, Qms 6.7 Electrical Q-factor, Qes 0.42 Total Q-factor, Qts 0.40 Moving mass incl. air,Mms 42 g Force factor, Bl 7.6 Tm Equivalent volume, Vas 71 liters Compliance, Cms 0.77 mm/N Mechanical loss, Rms 1.1 kg/s Rated power handling* 90 W * IEC 268-5, T/S parameters measured on drive units that are broken in.