21″ / 533 mm
Nominal diameter
41 Hz
Resonance
0.32
Q factor
96 dB
Sensitivity
± 14 mm
Linear excursion
3600 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
Available on (affiliate link)
Amazon.com
$$$
Specifications
Sensitivity (1w, 1m, infinite baffle)
SPL1W
95.9
dB
Frequency response
31 - 1800
Hz
Thiele & Small parameters
Resonance frequency (free air)
fS
41.0
Hz
Mechanical quality factor
QMS
10.56
Electrical quality factor
QES
0.33
Total quality factor
QTS
0.32
Large signal parameters
Maximum linear excursion
xmax
14.0
mm
Air volume displaced at xmax
VD
2327
cm³
Power handling
P
1800
W
Program power
Pmax
3600
W
Voice Coil
Nominal impedance
Z
4
Ω
DC resistance
RE
3.0
Ω
Inductance (1kHz)
LE
2.18
mH
VC Diameter
135
mm
Magnet
Force factor
Bl
32.7
N/A
Motor constant
Bl/√RE
18.9
N/√W
Diaphragm
Effective diameter
460
mm
Effective area
SD
1662
cm²
Moving mass
MMS
450
g
Moving mass (without air load)
MMD
402.5
g
Material
Weather protected
Suspensions
Stiffness
KMS
30.3
N/mm
Compliance
CMS
33
µm/N
Equivalent volume to the compliance
VAS
123
L
Mechanical resistance
RMS
10.98
N·s/m
Spider material
Triple silicon
Dimensions
Nominal diameter
21
″
533
mm
Overall diameter
545
mm
Baffle cutout diameter
492
mm
Overall depth
250
mm
Flange thickness
18
mm
Mounting depth
232
mm
Volume occupied by the driver (estimated)
9.2
L
Net weight
13.5
kg
Similar subwoofers to Eighteen Sound 21NLW9601
21″Subwoofer
fS
37 Hz
SD
1662 cm²
25 - 2000 Hz
QTS
0.29
xmax
14.0 mm
SPL1W
96 dB
Bl/√RE
18
Pmax
3600 W
18″Subwoofer
fS
38 Hz
SD
1295 cm²
30 - 2300 Hz
QTS
0.28
xmax
14.0 mm
SPL1W
96 dB
Bl/√RE
15
Pmax
3600 W
18″Subwoofer
fS
37 Hz
SD
1225 cm²
30 - 1000 Hz
QTS
0.31
xmax
14.8 mm
SPL1W
95 dB
Bl/√RE
15
Pmax
3600 W