Model High-quality SQ midwoofer Diameter 165 mm / 6.5″ Power handling (RMS/max.) 140 / 200 Watts Impedance 4 Ohms Efficiency 89 dB Frequency Response 40 Hz – 5000 Hz Voice coil 38 mm / 1.5″ Cone Aluminum-ceramics Mounting Ø 144 mm / 5.67″ Mounting depth 70 mm / 2.76″ Resonance frequency (Fs) 38 Hz