21-in Woofer w/4000 W continuous program power capacity, Neodymium magnet, 8 Ohms

4000 W continuous program power capacity153 mm 6 in split winding copper voice coil30 - 1000 Hz response96 dB sensitivity60 mm peak-to-peak excursion before damageNeodymium magnet allows a very high force factor & linear excursionDouble silicone spider w/optimized complianceVentilated voice coil gap for reduced power compressionAluminium demodulating ring for very low distortion4 ohmNominal Impedance4.2 ohmMinimum Impedance4000 WContinuous Power Handling2000 WNominal Power Handling AES96 dBSensitivity 1W/1m30 - 1000 HzFrequency Range153 mm 6 inVoice Coil DiameterCopperWinding MaterialGlass FibreFormer MaterialNeodymium RingMagnet Material30 mm 1.18 inWinding Depth12 mm 0.5 inMagnetic Gap Depth1.2 TFlux DensityDesignTriple RollSurround ShapeRadialCone ShapeNeodymium RingMagnet TypeDouble SiliconeSpiderT-PolePole Design190 dm3 6.71 ft3Recommended enclosure volume33 HzRecommended tuning frequencyParameters32 HzFs3.4 ohmRe0.31Qes7Qms0.3Qts200 dm3 7.00 ft3Vas1680 cm2 260.40 in2Sd2.2 %η0 +/- 15 mmXmax +/- 16 mmXvar460 gMms32.5 TxmBl1.5 mHLe103 HzEBPMounting & Shipping info547 mm 21.5 inOverall Diameter527 mm 20.7 inBolt Circle Diameter508 mm 20 inBaffle Cutout Diameter261 mm 10.3 inDepth0.63 mm 16 inFlange & Gasket Thickness16 dm3 0.56 ft3Air volume occupied by driver18.5 kg 40.7 lbNet Weight20.9 kg 46 lbShipping Weight590x590x300 mm 23.2x23.2x11.8 inShipping BoxRCK21SW1524Service kit