M21WO39-04

Transducer Size (Millimeters)203.2
DC Resistance2.83
Resonant Frequency30.9
Half Space Sensitivity93.79
Rated Noise Power80
Test Spectrum Bandwidth20Hz-10KHz

Transducer Size (Millimeters)203.2
DC Resistance2.83 Ω±5.0%
Resonant Frequency30.9 Hz15%
Half Space Sensitivity @ 2.83V93.79 dB±1.01
Sensitivity @ 1W/1m90.5 dB±1.01
Rated Noise Power (IEC 268-5 18.1)80 W
Test Spectrum Bandwidth20Hz-10KHz 12 dB/Oc
Effective Piston Area240.5 cm2
Moving Mass27.1 g
Motor Force Factor6.76 T•m
Voice Coil Inner Diameter38.6 mm
Gap Height6 mm
Maximum Linear Excursion5.9 mm
Ferrofluid Type
Minimum Impedance3.75 Ω±7.5%
Voice Coil Inductance0.24 mH
Mechanical Q Factor2.84
Electrical Q Factor0.33
Total Q Factor0.29
Ratio105.8 fs/Qts
Energy Bandwidth Product ((1/Qes)•fs)
Suspension Compliance980.4 μm/N
Effective Cone Diameter17.5 cm
Motor Efficiency Factor16.1 (T•m2)/Ω
Voice Coil Former MaterialASV
Transducer Mass1.86 Kg
Equivalent Volume79.67 L

This 4 ohm 8 inch driver is a member of the high performance M family. A powerful ferrite magnet system is coupled to a finite element analysis designed suspension system, containing both a linear spider design and a rubber surround.The long-throw voice coil ensures linear high excursion performance, needed for signal clarity. The cone necks are vented so as to reduce air compression effects under high excursion conditions. The cast aluminium basket offers structural rigidity, heat sinking capacity for the motor, and additional air venting under the spider so as to again reduce air compression effects. The cone in this model is a coated paper cone, offering a unique visual and acoustic experience.