The LF21N451 is a very high power handling and efficiency transducer specially designed to provide powerful and accurate sub-bass frequencies with low distortion and low power compression. The height of the voice coil has been specifically designed to improve the excursion and linearity at very low frequencies. The LF21N451 uses a special RCF developed carbon fibre + nylon + cellulose composite pulp which reinforces and improves the rigidity of the cone structure.
The new pulp and the large triple roll surround along double silicon spider system ensure excellent control and makes the cone resistant to deformation caused by very large displacements and pressure created by the transducer's high excursion behaviour. A fully optimised T-pole design generate the minimum amount of flux modulation. The dual-forced air venting system provides a very efficient voice coil ventilation to minimize the power compression.
• 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 designed with silicon based damping control
• BL of 34.5 Txm to provide a faster and accurate low frequency
General specifications
Cone Design: Curved
Dual-force air ventilation: Yes
Effective piston diameter: 470 mm / 18.5 inch
Frequency range: 30 - 1000 Hz
Kind of layers: inside/outside
Magnets: Neodymium
Max. Excursion Before Damage: 58 mm / 2.28 inch
Minimim Impedance: 7 ohm
Nominal Diameter: 21 inch / 533 mm
Number of layers: 2
Power handling capacity: 1500 W
Program Power: 3000 W
Rated Impedance: 8 ohm
Sensitivity: 98 dB
Spider: Dual with silicon based damping control
Surround Design: Triple roll
Surround Material: Polycotton
Top Plate Thickness: 15 mm / 0.59 inch
Voice Coil Diameter: 4.5 inch / 114 mm
Voice Coil Material: Copper
Voice Coil Winding Material: 34 mm / 1.34 inch
Mounting Information
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
Overall diameter: 547 mm / 21.54 inches
Rear mount baffle cut-out: 512 mm / 20.16 inch
Volume occupied by the driver: 6.5 liters / 0.26 ft3
Size
Diameter: 547 mm / 21.54 inches
Height: 249 mm / 9.8 inches
Weight: 10.9 kg / 24.03 lbs
Standard compliance
CE marking: Yes
Thiele - small parameters
BL factor (BL): 34.50 T x m
DC resistance (Re): 5.60 ohm
Effective moving mass (Mms): 315 gr
Effettive piston area (Sd): 0.17 m2
Electrical factor (Qes): 0.27 Qes
Equivalent Cas air loaded (Vas): 375 liters
Half-space efficency (Eff): 4.00%
Max. linear excursion (Xmax): 13 mm
Mechanical factor: 6.10 Qms
Resonance frequency (Fs): 30 Hz
Total factor: 0.26 Qts
Voice coil inductance @ 1kHz (Le1k): 3.00 mH
California Prop 65 -
WARNING: Cancer and Reproductive Harm -
www.P65Warnings.ca.gov