Sundown Audio U 6.5" D4 Subwoofer | 400 Watts RMS

Experience the power of deep, precise bass with the Sundown Audio U 6.5" D4 Subwoofer, engineered to deliver 400 watts RMS. This subwoofer is optimized for small ported enclosures, making it the perfect choice for high-power underseat setups or any compact space where quality bass is a must. Whether you're setting up a competition-level audio system or enhancing your daily drive, the U Series stands out as the premier “standard suspension” woofer in the Sundown lineup.

Built for Power and Precision

The U 6.5" D4 Subwoofer features dual 4-ohm voice coils, providing flexibility in wiring configurations to suit your audio needs. Its 1.75” aluminum voice coil former ensures superior heat dissipation, while the high-temperature copper voice coil can handle intense power levels without compromising on performance. The heavy-duty cast basket and double-stitched surround are designed for durability, ensuring your subwoofer can withstand the demands of high-powered audio environments.

Advanced Cooling for Consistent Performance

This subwoofer is designed with top-tier cooling technology to maintain optimal performance, even under high stress. The solid pole with vent channels and aluminum shorting ring cap minimizes inductive distortions, while the rear gap-venting and top-plate cooling channels keep the temperature in check, ensuring the subwoofer operates efficiently during extended play.

Versatile and Reliable

The U Series subwoofers are built to excel in various environments, from competition lanes to daily driving. The double-stacked 9” wide ferrite magnet system, coupled with a thick top plate, enhances performance. Shorting rings within the magnets and pole cap improve frequency response and act as both a heat sink and airflow guide. The custom aluminum frame, significantly thicker and equipped with heat-dissipation ribs, ensures the U 6.5" D4 remains cool and controlled even during intense use.

Key Features

• Power Handling: 400 Watts RMS for impactful, precise bass
• Voice Coil: Dual 4 Ohm for flexible wiring options
• Enclosure Compatibility: Optimized for small ported enclosures
• Cooling: Rear gap-venting and top-plate cooling channels for consistent performance
• Construction: Heavy-duty cast basket with double-stitched surround
• Connectivity: Spring-loaded terminals accepting up to 8-gauge wire
• Design: Ideal for both competition setups and high-performance daily driving

Technical Specifications

• T/S Specs (D4 Version):
  • RE (Ohms): 6.6274
  • FS (Hz): 38.6925
  • VAS (L): 3.7701
  • Qes: 0.5005
  • Qms: 7.2470
  • Qts: 0.4681
  • Le (mH): 5.5892
  • BL (NA): 20.0082
  • Mms (Grams): 124.3518
  • Cms (uM/N): 136.0613
  • Sensitivity (dB @ 1w/1m): 78.1460 dB

Sundown Audio U 6.5" Dimensions

Enclosure Recommendations

• Sealed Enclosure: 0.125-0.2 cu. ft. net
• Ported Enclosure: 0.25-0.35 cu. ft. net
• Recommended Tuning: 35Hz - 40Hz
• Recommended Port Area: 4-5 sq. in.
• Displacement: 0.04 cu. ft.
• Physical Dimensions:
  • Depth: 5.71"
  • Outside Diameter: 7.17"
  • Cut-Out Diameter: 5.94"

Upgrade your audio system with the Sundown Audio U 6.5" D4 Subwoofer. With its perfect blend of power, precision, and durability, it's the ideal choice for audiophiles seeking deep, impactful bass in a compact form. Whether you’re competing or just enjoying your favorite tunes, the U Series is built to deliver.