21″ / 533 mm
Nominal diameter
27 Hz
Resonance
0.38
Q factor
94 dB
Sensitivity
± 15 mm
Linear excursion
3200 W
Program Power
Driver
Port
Combined
Frequency response
Hz
Impedance
Ω
Impedance Phase
°
Excursion
mm
Velocity
m/s
SPL
dB
Acoustical Phase
°
Group Delay
ms
Transient response
ms
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Specifications
Sensitivity (1w, 1m, infinite baffle)
SPL1W
94.1
dB
Frequency response
30 - 1800
Hz
Thiele & Small parameters
Resonance frequency (free air)
fS
27.0
Hz
Mechanical quality factor
QMS
16.30
Electrical quality factor
QES
0.39
Total quality factor
QTS
0.38
Large signal parameters
Maximum linear excursion
xmax
15.0
mm
Air volume displaced at xmax
VD
2490
cm³
Power handling
P
1600
W
Program power
Pmax
3200
W
Voice Coil
Nominal impedance
Z
4
Ω
DC resistance
RE
2.6
Ω
Inductance (1kHz)
LE
1.3
mH
VC Diameter
100
mm
Magnet
Force factor
Bl
20.0
N/A
Motor constant
Bl/√RE
12.4
N/√W
Diaphragm
Effective diameter
460
mm
Effective area
SD
1660
cm²
Moving mass
MMS
355
g
Moving mass (without air load)
MMD
307.5
g
Material
Weather protected
Suspensions
Stiffness
KMS
10.2
N/mm
Compliance
CMS
98
µm/N
Equivalent volume to the compliance
VAS
380
L
Mechanical resistance
RMS
3.69
N·s/m
Dimensions
Nominal diameter
21
″
533
mm
Overall diameter
545
mm
Baffle cutout diameter
492
mm
Overall depth
245
mm
Flange thickness
18
mm
Mounting depth
227
mm
Volume occupied by the driver (estimated)
8.2
L
Net weight
11.6
kg
Similar subwoofers to Eighteen Sound 21NLW4000
21″Woofer
fS
28 Hz
SD
1700 cm²
28 - 1000 Hz
QTS
0.37
xmax
14.0 mm
SPL1W
95 dB
Bl/√RE
13
Pmax
4000 W
18″Woofer
fS
28 Hz
SD
1241 cm²
26 - 2000 Hz
QTS
0.33
xmax
6.0 mm
SPL1W
95 dB
Bl/√RE
9.42
Pmax
1000 W
18″Subwoofer
fS
28 Hz
SD
1225 cm²
40 - 400 Hz
QTS
0.42
xmax
12.0 mm
SPL1W
94 dB
Bl/√RE
8.84
Pmax
1600 W