Features
  • 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.


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Part number:

11100076
LF21N551
8ohm

Specifications
General specifications
Nominal Diameter
21 inch / 533 mm
Rated Impedance
8 ohm
Program Power (watt)
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
Minimum Impedance (ohm)
7.1 ohm
Voice Coil Diameter
5.3 inch / 135 mm
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 Design
Triple roll
Dual-force air ventilation
Yes
Thiele - small parameters
Resonance frequency (Fs)
35 Hz
DC resistance (Re) (ohm)
5.20 ohm
Mechanical factor
6.20 Qms
Electrical factor
0.35 Qes
Total factor
0.33 Qts
Bl factor (Bl) (T x m)
39.00 T x m
Effective moving mass (Mms)
434.0 g
Equivalent Cas air loaded (Vas)
200.0 liters
Effective piston area (Sd)
0.170 m2
Max. linear excursion (Xmax)
15 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
Size
Height
260 mm / 10.24 inches
Diameter
547 mm / 21.54 inches
Weight
14 kg / 30.86 lbs
Shipping information
Package Height
284 mm / 11.18 inches
Package Width
604 mm / 23.78 inches
Package Depth
584 mm / 22.99 inches
Package Weight
17 kg / 37.48 lbs
Downloads
SPECSHEETS
PDF
1,001 KB
22-01-2024
DRAWINGS
DXF
2.5 MB
22-01-2024
PDF
554 KB
22-01-2024
PDF
477 KB
21-03-2018