U-Series v.2 18" Subwoofer
Notice On Packaging For Subwoofers
Sundown Audio has led the industry in quality and performance for over a decade. To improve accuracy and transparency, we have updated our subwoofer power ratings to reflect true real-world performance.
During this transition, some packaging may show previous ratings. Performance fully aligns with our current published specifications. If you have any questions about authenticity or ratings, please contact directly for confirmation.
- 2000 Watts RMS / 4000 Watts Peak
- Dual 2 or 4 ohm voice coils
- Optimized for small ported or bandpass enclosures
- Aluminum 3” voice coil former for superior heat dissipation
- High-temperature copper voice coil
- Double stitched surround
- Heavy-duty cast basket
- Spring-loaded terminals accept up to 8-gauge wire
- Stitched-on heavy-duty tinsel leads
- Solid pole with vent channels and aluminum shorting ring cap
- Rear gap-venting
- Top-Plate Cooling Channels
Designed to be at home in the competition lanes or playing your favorite music, the U Series is the premier “standard suspension” woofer in the Sundown lineup. A double-stacked 9.4-inch wide ferrite magnet system is coupled to a thick top plate. A thick set of shorting rings are used inside the magnets and on the pole cap, smoothing out frequency response while doubling as a heat sink and airflow guide. A custom aluminum frame was designed specifically for the U Series. It’s substantially thicker and equipped with heat dissipation ribs at the bottom of the frame. The U v.2 motor also features an extended pole piece to keep the coil under perfect control under high stress. The coil temperature is controlled with machined, high-velocity pole channels and a series of 16 direct air-gap vents in the back plate.
Dimensions
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| Parameter | D2 Model | D4 Model |
|---|---|---|
| Re | 3.87 Ω | 6.07 Ω |
| Fs | 30.9 Hz | 30.9 Hz |
| Qms | 5.6300 | 5.5100 |
| Qes | 0.5660 | 0.6500 |
| Qts | 0.5100 | 0.5800 |
| Vas | 111.760 L | 114.690 L |
| Mms | 565.41 g | 552.15 g |
| Cms | 0.05 mm/N | 0.05 mm/N |
| BL | 27.402 T·m | 31.490 T·m |
| Le | 3.39 mH | 4.74 mH |
| Sd | 1641.9 cm² | 1641.9 cm² |
| Xmax | 30mm | 30mm |
| SPL (1W/1m) | 92.6 dB | 90.0 dB |
| Specification | D2 Model | D4 Model |
|---|---|---|
| RMS Power | 2000 W | 2000 W |
| Peak Power | 4000 W | 4000 W |
| Displacement | .26cu ft | .26cu ft |
| Mounting Depth | 10" | 10" |
| Outside Diameter | 18.63" | 18.63" |
| Cutout Diameter | 16.9" | 16.9" |
| Motor Diameter | 9.7" | 9.7" |
| Sealed Enclosure | 3.0cu ft | 3.0cu ft |
| Ported Enclosure | 4.0cu ft | 4.0cu ft |
| Recommended Port Tuning | 35hz | 35hz |
| Recommended Port Area | 64sq in | 64sq in |
| Xmax | 30mm | 30mm |
| 4th Order Sealed | 2.25cu ft | 2.25cu ft |
| 4th Order Ported | 6.75cu ft | 6.75cu ft |
| 4th Order Port Area | 135sq in | 135sq in |
| 4th Order Port Length | 6" | 6" |
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