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Sundown Audio U-6.5SW (Open Box, Great)

400W RMS 6.5" U Series Dual 4-ohm Car Subwoofer

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• RMS Power: 400 watts
• Impedance: Dual 4 ohm
• Mount depth: 5.71"
• Sensitivity: 78.1460 dB

Learn more about the ls-uv165d4-u8

We apologize

This item has been discontinued

Description


Sundown Audio brand icon

Authorized dealer

Item Condition - Open Box, Great:

This product works like new, is well-cared-for and in great condition. May show limited signs of wear or use and may be missing non-essential parts, accessories or original packaging.


Sundown Audio SW-UV16.5D4

Perfect for high-power underseat enclosures and designed to be at home in the competition lanes or playing your favorite tunes, the U Series is the premier “standard suspension” woofer in the Sundown lineup. A double-stacked 9” wide ferrite magnet system is coupled to a thick top plate. A thick set of shorting rings are also used inside the magnets and on the pole cap, smoothing out frequency response while doubling as a heat sink and airflow guide. An all-new, substantially thicker custom aluminum frame was designed specifically for the U Series, and equipped with heat-dissipation ribs. The motor also features an extended pole piece to keep the coil controlled under high stress!


Product Details:

  • 6.5" Dual 4 ohm U Series Subwoofer
  • Power Handling:
    • RMS: 400 watts
  • Optimized for small ported enclosures
  • 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
  • 1.75" High Temperature Aluminum Voice coil
  • 19 mm Xmax
  • Double Stacked Ferrite magnet motor structure
  • Resonance Frequency (Fs): 38.6925 Hz
  • Sensitivity: 78.1460 dB
  • Recommended sealed box volume: 0.125 cubic feet - 0.2 cubic feet
  • Recommended ported box volume: 0.25 cubic feet - 0.35 cubic feet
  • Top-mount depth: 5.71"
  • Cutout diameter: 5.94"
  • Authorized Internet Dealer
  • 1-year Manufacturer's Warranty

  • Priced Individually

Subwoofer Wiring Guide


Wiring Guide to Wire 1 Sundown Audio U-6.5SW (Open Box, Great) Subwoofer

Mono Amp

2 Channel Amp - Bridged

Wiring Guide to Wire 2 Sundown Audio U-6.5SW (Open Box, Great) Subwoofers

Mono Amp

Mono Amp - Option 1

2 Channel Amp

2 Channel Amp - Bridged

4 Channel Amp - Bridged

Wiring Guide to Wire 3 Sundown Audio U-6.5SW (Open Box, Great) Subwoofers

Mono Amp

4 Channel Amp

Wiring Guide to Wire 4 Sundown Audio U-6.5SW (Open Box, Great) Subwoofers

Mono Amp

2 Channel Amp

2 Channel Amp - Bridged

4 Channel Amp

Specifications & Details


Subwoofer Specifications
Series
U Series
Subwoofer Size
6.5"
RMS Power Handling
400 watts
Voice Coil(s)
Dual
Impedance (Per Voice Coil)
4 ohm
Voice Coil Material
Aluminum
Voice Coil Diameter
1.75"
Sensitivity
78.1460 dB
Xmax (millimeters)
19 mm
Subwoofer Design
Round / Circle
Main Cone Color
Black
Magnet Structure
Double Stacked
Magnet Type
Ferrite
Recommended Enclosure Specifications
Recommended Enclosure Type
Ported / Vented
Sealed
Minimum Sealed Box Volume
0.125 cubic feet
Maximum Sealed Box Volume
0.2 cubic feet
Minimum Ported Box Volume
0.25 cubic feet
Maximum Ported Box Volume
0.35 cubic feet
Top-Mount Depth (Mounting Depth)
5.71"
Cutout Diameter
5.94"
Shallow Mount Installation
No
T/S Parameters (Electromechanical)
Free-Air Resonance (Fs)
38.6925 Hz
Equivalent Compliance (Vas)
3.7701 liters
Total Speaker Q Value (Qts)
0.4681
Electrical Q Value (Qes)
0.5005
Electrical Resistance of Voice Coil (Re)
6.6274 ohm
Mechanical Q Value (Qms)
7.2470
What is in the box?
WITB: Subwoofers
Subwoofer
Warranty and Return Policy
Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider
Manufacturer

Item Details


Manufacturer:

Model Number:

SW-UV16.5D4-2

Weight:

16.00lbs

Internal SKU:

ls-uv165d4-u8

Internal Product ID:

217797

Customer Ratings & Reviews


Sundown Audio U-6.5SW (Open Box, Great) thumbnail image

5 star
100%
4 star
0%
3 star
0%
2 star
0%
1 star
0%



Durability
5
Value
5
Features
5
Design
5
Usability
5

Customer Photos & Videos


Customer Reviews

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Impressive “little” things

Hard to believe how massive a 6.5” could be. These are monsters! Extremely well built, just like you would expect from sundown audio. If you’re looking for bass in a small space, these are definitely something you’ll want to look into.

By Greg on August 31, 2025 Checkmark Icon Verified purchase



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