Sundown U-8 V.1

The Sundown Audio U-8 V.1 combines compact dimensions with high power handling and an exceptionally long cone excursion. The 8-inch subwoofer is particularly well-suited for high-performance car audio systems that require a powerful, deep bass foundation despite limited space.

With a power handling capacity of 750 watts RMS and a linear Xmax of 18 mm in one direction, the U-8 V.1 offers impressive headroom for a subwoofer in this size class. Sundown Audio uses a 2.25-inch voice coil with an aluminum carrier and high-temperature-resistant copper wire. The design supports efficient heat dissipation and enables a high continuous power handling capacity.

A solid die-cast aluminum basket forms the mechanical foundation. The double-stitched surround and robust, stitched tinsel leads are designed for high excursion and demanding operation. Additional cooling channels on the top plate and rear air gap ventilation support thermal management of the voice coil.

The U-8 V.1 was developed specifically for compact bass-reflex enclosures. For a typical bass-reflex application, Sundown Audio recommends a net volume of approximately 0.65 ft³ (about 18.4 liters) tuned to 35 Hz. This allows for a powerful bass system with good depth despite the small driver size.

Technical Specifications

• Manufacturer: Sundown Audio
• Model: U-8 V.1
• Series: U-Series
• Subwoofer size: 8 inches / approx. 20 cm
• RMS Power Handling: 750 watts
• Peak Power Handling: 1,500 watts
• Voice coil: 2.25 inches
• Voice coil former: Aluminum
• Voice coil wire: high-temperature-resistant copper
• Voice coil options: Dual 2 ohms (D2) or Dual 4 ohms (D4)
• Xmax: 18 mm linear, single-sided
• Effective membrane area Sd: 344.8 cm²
• Sturdy die-cast aluminum basket
• Double-stitched piping
• Sturdy, stitched tinsel leads
• Spring-loaded speaker terminals
• Terminal wire capacity: up to 8 AWG
• Rear Air Gap Ventilation
• Cooling channels in the top plate
• Core with ventilation channels
• Aluminum Short-Circuit Ring
• Optimized for compact bass-reflex enclosures
  
  

T/S Parameters – U-8 V.1 D2

• Voice coil impedance: Dual 2 ohms
• Resonance frequency Fs: 39.39 Hz
• DC resistance: 3.80 ohms
• Mechanical Grade Qms: 2.474
• Electrical quality Qes: 0.412
• Total quality Qts: 0.353
• Equivalent volume (Vas): 6.35 liters
• Mass in motion (Mms): 175.34 g
• Elasticity (cm/N): 93.13 µm/N
• Effective membrane area Sd: 344.8 cm²
• BL Force Factor: 20.00 Tm
• Efficiency: 81.6 dB
• Xmax: 18 mm
  
  

T/S Parameters – U-8 V.1 D4

• Voice coil impedance: Dual 4 ohms
• Resonance frequency Fs: 41.29 Hz
• DC resistance Re: 6.34 ohms
• Mechanical Grade Qms: 2.542
• Electrical quality Qes: 0.519
• Total quality (Qts): 0.431
• Equivalent volume (Vas): 6.97 liters
• Mass in motion (Mms): 145.24 g
• Elasticity (cm): 102.31 µm/N
• Effective membrane area Sd: 344.8 cm²
• BL Force Factor: 21.45 Tm
• Efficiency: 82.7 dB
• Xmax: 18 mm
  
  

Dimensions

• Outer diameter: 8.70 inches / approx. 221 mm
• Installation diameter: 7.375 inches / approx. 187 mm
• Mounting depth: 6.02 inches / approx. 153 mm
• Motor diameter: 6.88 inches / approx. 175 mm
• Subwoofer displacement: 0.09 ft³ / approx. 2.55 liters
  
  

Manufacturer's Recommendation for the Housing

• Sealed enclosure: 0.25–0.35 ft³ / approx. 7.1–9.9 liters
• Bass-reflex enclosure: 0.65 ft³ / approx. 18.4 liters
• Recommended bass-reflex tuning: 35 Hz
• Recommended port area: 9 in² / approx. 58 cm²
  
  

4th-Order Bandpass Recommendation

• Sealed chamber: 0.225 ft³ / approx. 6.4 liters
• Ventilated chamber: 0.675 ft³ / approx. 19.1 liters
• Port area: 14 in² / approx. 90.3 cm²
• Port length: 6 inches / approx. 15.2 cm
  
  

The Sundown Audio U-8 V.1 is therefore an interesting solution for compact yet high-performance subwoofer systems. In particular, the combination of its 8-inch size, 750-watt RMS power handling, and 18-mm linear excursion makes it ideal for installations where space is limited but bass performance should be prioritized as much as possible.