Speaker 21", 1500W, 98.5dB, 30-1000Hz, The LF21N451 is a high-power handling and efficiency transducer designed to deliver powerful and precise sub-bass frequencies with minimal distortion and power compression. Its voice coil height is optimized to enhance excursion and linearity at low frequencies. The LF21N451 features a special RCF-developed cone structure made of carbon fiber, nylon, and cellulose composite pulp for increased rigidity. The large triple roll surround and dual silicon spider system provide excellent control and resistance to deformation under high excursion conditions. The T-pole design minimizes flux modulation, while the dual-forced air venting system ensures efficient voice coil ventilation to reduce power compression. Features: - 4.5-inch Inside/Outside copper voice coil - 3000 Watt continuous program power handling - 98.5 dB Sensitivity - 30 Hz - 1 kHz Frequency range - Dual-forced air ventilation for minimum power compression - Dual spider design with silicon-based damping control - BL of 34.5 Txm for faster and accurate low frequency response General Specifications: - Nominal Diameter: 530 / 21 mm/inch - Rated Impedance: 8 ohm - Program Power: 3000 W AES - Power handling capacity: 1500 W AES - Sensitivity: 98.5 dB - Frequency Range: 30 Hz ÷ 1000 Hz - Effective Piston Diameter: 470 / 18.5 mm/inch - Max Excursion Before Damage (peak to peak): 58 / 2.28 mm/inch - Minimum Impedance: 7.1 ohm - Voice Coil Diameter: 115 / 4.5 mm/inch - Voice Coil Material: Copper - Voice Coil Winding Depth: 34 / 1.33 mm/inch - Number of layers: 2 - Kind of layer: inside / outside - Top Plate Thickness: 15 / 0.6 mm/inch - Cone Material: No pressed pulp carbon fiber reinforced - Cone Design: Curved - Surround Material: Polycotton - Surround Design: Triple roll Thiele/Small Parameters: - DC resistance: 5.6ohm - Mechanical factor: 6 - Electrical factor: 0.27 - Total factor: 0.26 - BL Factor: 34.5 T · m - Effective Moving Mass: 315 g - Equivalent Cas air load: 375 liters - Effective piston area: 0.173 m2 - Max. linear excursion (mathematical): 1>3.2 mm - Voice-coil inductance @ 1kHz: 3.0 mH - Half-space efficiency: 4.0% Mounting information: - Overall Diameter: 547 / 21.5 mm/inch - Bolt Circle Diameter: 527 / 20.7 mm/inch - Bolt Hole Diameter: 6.5 / 0.25 mm/inch - Front Mount Baffle Cut-out: 512 / 20.1 mm/inch - Rear Mount Baffle Cut-out: 512 / 20.1 mm/inch - Depth: 250 / 9.8 mm/inch Volume occupied by the driver: 6.5 / 0.229 liters/ft3 - Net Weight: 10.9 / 24 kg/lbs Shipping information: - Shipping weight: 12.1 / 26.6 kg/lbs