The RCF LF21X451 is a premium 21-inch subwoofer built for ultra-high-output low-frequency performance. Featuring a robust 4.5-inch inside/outside copper voice coil, dual-forced air ventilation, and a fiber-loaded cone, this transducer delivers deep bass, exceptional linearity, and maximum reliability. With 4000W program power handling and high excursion capability, it’s engineered for demanding professional audio applications requiring both punch and precision.
Product Specifications:
Nominal Diameter: 21″
Rated Impedance: 8 ohm
Program Power: 4000 W
Power Handling (AES): 2000 W
Sensitivity: 97 dB
Frequency Range: 28 Hz – 1 kHz
Voice Coil Diameter: 4.5″
Voice Coil Material: Copper
Voice Coil Design: Inside/Outside, 2 layers
Voice Coil Length: 1.34″
Magnet Type: Ceramic
Top Plate Thickness: 0.59″
BL Factor: 30.5 T·m
Inductance (1 kHz): 2.90 mH
Mechanical
Cone: Fiber-loaded, curved design
Surround: Triple-roll polycotton
Spider: Dual with silicon-based damping
Max Excursion (Before Damage): 2.13″
Xmax (Linear Excursion): 0.55″
Thiele-Small Parameters
Resonance Frequency (Fs): 28 Hz
DC Resistance (Re): 5.40 ohm
Qms: 6.90
Qes: 0.39
Qts: 0.37
Moving Mass (Mms): 355 g
Vas: 385 L
Sd: 0.170 m²
Efficiency (Half-space): 2.20%
Mounting Information (Inches)
Overall Diameter: 21.54″
Bolt Circle Diameter: 20.75″
Bolt Hole Diameter: 0.28″
Baffle Cut-out (Front/Rear): 20.16″
Driver Depth (Height): 9.65″
Driver Volume Occupied: 0.26 ft³
Dimensions & Weight
Height: 9.65″
Diameter: 21.54″
Weight: 34.17 lbs
Package (H x W x D): 11.18″ x 22.99″ x 23.78″
Shipping Weight: 40.79 lbs
