Rockford Fosgate RM18D4
2x2Ω
2x4Ω
Subwoofer
8″ / 203 mm
Nominal diameter
42 Hz
Resonance
0.81
Q factor
85 dB
Sensitivity
± 7 mm
Linear excursion
300 W
Program Power
- Sensitivity (1W, 1m, infinite baffle)
- SPL1W
- 84.5
- dB
- Resonance frequency (free air)
- fS
- 41.5
- Hz
- Mechanical quality factor
- QMS
- 8.48
- Electrical quality factor
- QES
- 0.89
- Total quality factor
- QTS
- 0.81
- Maximum linear excursion
- xmax
- 7.0
- mm
- Air volume displaced at xmax
- VD
- 194
- cm³
- Power handling
- P
- 150
- W
- Program power
- Pmax
- 300
- W
- Nominal impedance
- Z
- 2 x 4
- Ω
- DC resistance (in series)
- RE
- 6.3
- Ω
- Inductance (1kHz, in series)
- LE
- 2.48
- mH
- VC Diameter
- 38
- mm
- Former material
- Aluminum
- Force factor (in series)
- Bl
- 12.5
- N/A
- Motor constant
- Bl/√RE
- 4.98
- N/√W
- Weight
- 0.5
- kg
- Effective diameter
- 188
- mm
- Effective area
- SD
- 277
- cm²
- Moving mass
- MMS
- 84
- g
- Moving mass (without air load)
- MMD
- 81.1
- g
- Stiffness
- KMS
- 5.71
- N/mm
- Compliance
- CMS
- 175
- µm/N
- Equivalent volume to the compliance
- VAS
- 19
- L
- Mechanical resistance
- RMS
- 2.58
- N·s/m
- Nominal diameter
- 8
- ″
- 203
- mm
- Baffle cutout diameter
- 177
- mm
- Mounting depth
- 92
- mm
- Volume occupied by the driver
- 1.42
- L