{"product_id":"lf21x451","title":"RCF LF21X451 Woofer","description":"\u003cp\u003eThe LF21X451 low frequency transducer is the result of many years of R\u0026amp;D developments with the goal of creating new levels of professional audio performance standards. This products features advancements and improvements in all the key areas of transducer technology. Incredibly linear frequency response characteristics, the highest power handling of any comparable transducer, the lowest power compression. The LF21X451 features a fibre loaded cone assembly along with a high excursion triple roll, constant geometry surround: this combination provides remarkable strength and a peak to peak maximum excursion of 54 mm. The new dual forced hyper-venting system guarantee a very efficient voice coil ventilation for minimum power compression and incredible power handling.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eFeatures\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e4,5 - inch fiberglass Inside\/Outside copper voice coil\u003c\/li\u003e\n\u003cli\u003e4000 Watt continuous program power handling\u003c\/li\u003e\n\u003cli\u003e97 dB Sensitivity\u003c\/li\u003e\n\u003cli\u003e28 Hz - 1 kHz Frequency range\u003c\/li\u003e\n\u003cli\u003eDual-forced air ventilation for minimum power compression\u003c\/li\u003e\n\u003cli\u003eDual spider designed with silicon based damping control\u003c\/li\u003e\n\u003cli\u003eBL of 30.5 Txm to provide a faster and accurate low frequency\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eSpecifications\u003c\/strong\u003e\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\u003ctd colspan=\"2\"\u003e\u003cstrong\u003eGeneral specifications\u003c\/strong\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNominal Diameter\u003c\/td\u003e\n\u003ctd\u003e21 inch \/ 533 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRated Impedance\u003c\/td\u003e\n\u003ctd\u003e8 ohm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProgram Power (watt)\u003c\/td\u003e\n\u003ctd\u003e4000 W\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower handling capacity\u003c\/td\u003e\n\u003ctd\u003e2000 W\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSensitivity\u003c\/td\u003e\n\u003ctd\u003e97.0 dB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFrequency range\u003c\/td\u003e\n\u003ctd\u003e28 - 1000 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEffective piston diameter\u003c\/td\u003e\n\u003ctd\u003e470 mm \/ 18.5 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMax. Excursion Before Damage\u003c\/td\u003e\n\u003ctd\u003e54 mm \/ 2.13 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMinimum Impedance (ohm)\u003c\/td\u003e\n\u003ctd\u003e6.7 ohm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVoice Coil Diameter\u003c\/td\u003e\n\u003ctd\u003e4.5 inch \/ 114 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVoice Coil Winding Material\u003c\/td\u003e\n\u003ctd\u003eCopper\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVoice Coil Length\u003c\/td\u003e\n\u003ctd\u003e34 mm \/ 1.34 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNumber of layers\u003c\/td\u003e\n\u003ctd\u003e2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eKind of layers\u003c\/td\u003e\n\u003ctd\u003einside\/outside\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTop Plate Thickness\u003c\/td\u003e\n\u003ctd\u003e15 mm \/ 0.59 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCone Design\u003c\/td\u003e\n\u003ctd\u003eCurved\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurround Material\u003c\/td\u003e\n\u003ctd\u003ePolycotton\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurround Design\u003c\/td\u003e\n\u003ctd\u003eTriple roll\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMagnets\u003c\/td\u003e\n\u003ctd\u003eCeramic\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDual-force air ventilation\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpider\u003c\/td\u003e\n\u003ctd\u003e03\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd colspan=\"2\"\u003e\u003cstrong\u003eThiele - small parameters\u003c\/strong\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eResonance frequency (Fs)\u003c\/td\u003e\n\u003ctd\u003e28 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDC resistance (Re) (ohm)\u003c\/td\u003e\n\u003ctd\u003e5.40 ohm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMechanical factor\u003c\/td\u003e\n\u003ctd\u003e6.90 Qms\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eElectrical factor\u003c\/td\u003e\n\u003ctd\u003e0.39 Qes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTotal factor\u003c\/td\u003e\n\u003ctd\u003e0.37 Qts\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBl factor (Bl) (T x m)\u003c\/td\u003e\n\u003ctd\u003e30.50 T x m\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEffective moving mass (Mms)\u003c\/td\u003e\n\u003ctd\u003e355.0 g\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEquivalent Cas air loaded (Vas)\u003c\/td\u003e\n\u003ctd\u003e385.0 liters\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEffective piston area (Sd)\u003c\/td\u003e\n\u003ctd\u003e0.170 m2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMax. linear excursion (Xmax)\u003c\/td\u003e\n\u003ctd\u003e14 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVoice coil inductance @ 1kHz (Le1k)\u003c\/td\u003e\n\u003ctd\u003e2.90 mH\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHalf-space efficency (Eff)\u003c\/td\u003e\n\u003ctd\u003e2.20%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd colspan=\"2\"\u003e\u003cstrong\u003eMounting information\u003c\/strong\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOverall diameter\u003c\/td\u003e\n\u003ctd\u003e547 mm \/ 21.54 inches\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBolt circle diameter\u003c\/td\u003e\n\u003ctd\u003e527 mm \/ 20.75 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBolt hole diameter\u003c\/td\u003e\n\u003ctd\u003e7 mm \/ 0.28 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFront mount baffle cut-out\u003c\/td\u003e\n\u003ctd\u003e512 mm \/ 20.16 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRear mount baffle cut-out\u003c\/td\u003e\n\u003ctd\u003e512 mm \/ 20.16 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolume occupied by the driver\u003c\/td\u003e\n\u003ctd\u003e6.5 liters \/ 0.26 ft3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd colspan=\"2\"\u003e\u003cstrong\u003eStandard compliance\u003c\/strong\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSafety agency\u003c\/td\u003e\n\u003ctd\u003eCE compliant\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd colspan=\"2\"\u003e\u003cstrong\u003eSize \/ Weight\u003c\/strong\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHeight\u003c\/td\u003e\n\u003ctd\u003e245 mm \/ 9.65 inches\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDiameter\u003c\/td\u003e\n\u003ctd\u003e547 mm \/ 21.54 inches\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e15.5 kg \/ 34.17 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd colspan=\"2\"\u003e\u003cstrong\u003eShipping information\u003c\/strong\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePackage Height\u003c\/td\u003e\n\u003ctd\u003e284 mm \/ 11.18 inches\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePackage Width\u003c\/td\u003e\n\u003ctd\u003e584 mm \/ 22.99 inches\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePackage Depth\u003c\/td\u003e\n\u003ctd\u003e604 mm \/ 23.78 inches\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePackage Weight\u003c\/td\u003e\n\u003ctd\u003e18.5 kg \/ 40.79 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e","brand":"RCF","offers":[{"title":"Default Title","offer_id":46528136052933,"sku":"LF21X451","price":849.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0603\/0612\/9093\/files\/000_LF21X451_singolo_gallery.png?v=1783905697","url":"https:\/\/www.prodj.com\/products\/lf21x451","provider":"ProDJ","version":"1.0","type":"link"}