- 5.3 – inch Inside/Outside copper voice coil
- 4000 Watt continuous program power handling
- 97 dB Sensitivity
- 30 Hz – 1 kHz Frequency range
- Dual-forced air ventilation for minimum power compression
- Dual spider designed with silicon based damping control
- BL of 39 Txm to provide a faster and accurate low frequency
The LF21N551 is very high power handling 21” neodymium woofer. The combination of a 3600 Watt power handling and a minimum weight of 13,7 Kg makes this transducer a unique product in his category. The transducer design is based on a very strong neodymium magnetic structure and a new 5,3” inside-outside copper coil. The new Dual forced design provide an excellent heat dissipation and lower power compression. Special air-forced ventilations are provided for voice coil, magnet assembly and basket. The combination of carbon fibre loaded cone assembly, large triple roll surround, double silicon spider provides to the LF21N551 remarkable strength and best control under large excursion conditions. A fully optimised T-pole design generate the minimum amount of flux modulation offering a peak to peak excursion of 72 mm. The waterproof body cone treatment and polycotton surround ensure a durable performance in every application.
- General specifications
- Nominal Diameter: 21 inch / 533 mm
- Rated Impedance: 8 ohm
- Program Power: 4000 W
- Power handling capacity: 2000 W
- Sensitivity: 97.0 dB
- Frequency range: 30 – 1000 Hz
- Effective piston diameter: 470 mm / 18.5 inch
- Max. Excursion Before Damage: 72 mm / 2.83 inch
- Minimim Impedance: 7.1 ohm
- Voice Coil Diameter: 5.3 inch / 135 mm
- Voice Coil Winding Material: Copper
- Voice Coil Length: 39 mm / 1.54 inch
- Number of layers: 2
- Kind of layers: inside/outside
- Top Plate Thickness: 18 mm / 0.71 inch
- Cone Design: Curved
- Surround Material: Polycotton
- Surround Design: Triple roll
- Magnets: Neodymium
- Dual-force air ventilation: Yes
- Spider: Dual with silicon based damping control
- Thiele – small parameters
- Resonance frequency (Fs): 35 Hz
- DC resistance (Re): 5.20 ohm
- Mechanical factor: 6.20 Qms
- Electrical factor (Qes): 0.35 Qes
- Total factor: 0.33 Qts
- BL factor (BL): 39.00 T x m
- Effective moving mass (Mms): 434.0 g
- Equivalent Cas air loaded (Vas): 200.0 liters
- Effettive piston area (Sd): 0.170 m2
- Max. linear excursion (Xmax): 15.0 mm
- Voice coil inductance @ 1kHz (Le1k): 3.20 mH
- Half-space efficency (Eff): 2.40%
- Mounting Information
- Overall diameter: 547 mm / 21.54 inches
- Bolt circle diameter: 527 mm / 20.75 inch
- Bolt hole diameter: 7 mm / 0.28 inch
- Front mount baffle cut-out: 512 mm / 20.16 inch
- Rear mount baffle cut-out: 512 mm / 20.16 inch
- Volume occupied by the driver: 7.2 liters / 0.28 ft3
- Standard compliance
- CE marking: Yes
- Size
- Weight: 14 kg / 30.86 lbs
- Height: 260 mm / 10.24 inches
- Diameter: 547 mm / 21.54 inches
- Shipping informations
- Package Width: 604 mm / 23.78 inches
- Package Weight: 17 kg / 37.48 lbs
- Package Height: 284 mm / 11.18 inches
- Package Depth: 584 mm / 22.99 inches
