Eighteen Sound 21iD
Subwoofer
21″ / 533 mm
Nominal diameter
38 Hz
Resonance
0.23
Q factor
96 dB
Sensitivity
± 14 mm
Linear excursion
3600 W
Program Power
![Eighteen Sound 21iD Subwoofer](/18Sound/21iD/18Sound_21iD_(Photo_1).jpg)
![Eighteen Sound 21iD Subwoofer](/18Sound/21iD/18Sound_21iD_(Photo_2).jpg)
- Sensitivity (1W, 1m, infinite baffle)
- SPL1W
- 96.2
- dB
- Frequency response
- 29 - 1600
- Hz
- Resonance frequency (free air)
- fS
- 38.0
- Hz
- Mechanical quality factor
- QMS
- 5.60
- Electrical quality factor
- QES
- 0.24
- Total quality factor
- QTS
- 0.23
- Maximum linear excursion
- xmax
- 14.0
- mm
- Air volume displaced at xmax
- VD
- 2324
- cm³
- Power handling
- P
- 1800
- W
- Program power
- Pmax
- 3600
- W
- Nominal impedance
- Z
- 2
- Ω
- DC resistance
- RE
- 1.3
- Ω
- Inductance (1kHz)
- LE
- 1.08
- mH
- VC Diameter
- 135
- mm
- Winding material
- Copper
- Force factor
- Bl
- 25.2
- N/A
- Motor constant
- Bl/√RE
- 22.1
- N/√W
- Material
- Neodymium
- Effective diameter
- 460
- mm
- Effective area
- SD
- 1660
- cm²
- Moving mass
- MMS
- 489
- g
- Moving mass (without air load)
- MMD
- 441.5
- g
- Material
- Water,UV repellent
- Stiffness
- KMS
- 27.78
- N/mm
- Compliance
- CMS
- 36
- µm/N
- Equivalent volume to the compliance
- VAS
- 143
- L
- Mechanical resistance
- RMS
- 20.85
- N·s/m
- 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
- 13.6
- kg
Thiele & Small parameters
Large signal parameters
Voice Coil
Magnet
Diaphragm
Suspensions
Dimensions
![Eighteen Sound 21iD Impedance](/18Sound/21iD/18Sound_21iD_(Impedance).png)
![Eighteen Sound 21iD SPL](/18Sound/21iD/18Sound_21iD_(Frequency_response).png)
![Eighteen Sound 21iD Dimensions](/18Sound/21iD/18Sound_21iD_(Dimensions).png)
Export this driver to a simulation software:
![WinISD](/images/export/WinISD.png)
![Basta!](/images/export/Basta.png)
![Hornresp](/images/export/Hornresp.png)
![QSpeakers](/images/export/QSpeakers.png)
![SpeakerSim](/images/export/SpeakerSim.png)
![MfbLabs](/images/export/MfbLabs.png)
![Speakerbench](/images/export/Speakerbench.png)