21″ / 533 mm
Nominal diameter
29 Hz
Resonance
0.37
Q factor
94 dB
Sensitivity
± 14 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
Sensitivity (1w, 1m, infinite baffle)
SPL1W
94.4
dB
Frequency response
30 - 1000
Hz
Thiele & Small parameters
Resonance frequency (free air)
fS
29.0
Hz
Mechanical quality factor
QMS
22.00
Electrical quality factor
QES
0.38
Total quality factor
QTS
0.37
Large signal parameters
Maximum linear excursion
xmax
14.0
mm
Maximum excursion before damage
xlim
35.0
mm
Air volume displaced at xmax
VD
2324
cm³
Power handling
P
1600
W
Program power
Pmax
3200
W
Voice Coil
Nominal impedance
Z
8
Ω
DC resistance
RE
4.9
Ω
Inductance (1kHz)
LE
2.58
mH
VC Diameter
100
mm
Magnet
Force factor
Bl
30.0
N/A
Motor constant
Bl/√RE
13.6
N/√W
Diaphragm
Effective diameter
460
mm
Effective area
SD
1660
cm²
Moving mass
MMS
380
g
Moving mass (without air load)
MMD
332.5
g
Material
Curved ribbed fiber loaded cellulose
Suspensions
Stiffness
KMS
12.82
N/mm
Compliance
CMS
78
µm/N
Equivalent volume to the compliance
VAS
305
L
Mechanical resistance
RMS
3.15
N·s/m
Surround material
Triple roll, Heavy Polycotton
Dimensions
Nominal diameter
21
″
533
mm
Overall diameter
545
mm
Baffle cutout diameter
490
mm
Overall depth
252
mm
Flange thickness
18
mm
Mounting depth
234
mm
Volume occupied by the driver (estimated)
11.0
L
Net weight
17.9
kg
Similar subwoofers to Eighteen Sound 21LW2500
21″Subwoofer
fS
29 Hz
SD
1660 cm²
30 - 1800 Hz
QTS
0.37
xmax
15.0 mm
SPL1W
94 dB
Bl/√RE
14
Pmax
3200 W
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
21″Subwoofer
fS
27 Hz
SD
1660 cm²
35 - 1400 Hz
QTS
0.33
xmax
14.6 mm
SPL1W
94 dB
Bl/√RE
14
Pmax
3200 W