Sundown SLD-12

The Sundown Audio SLD-12 is a powerful 12-inch shallow subwoofer designed for car audio installations where installation depth is limited but you still want powerful and controlled low-frequency bass. With a power handling capacity of 600 watts RMS and 1,200 watts peak, the SLD-12 offers ample power headroom despite an installation depth of only about 138 mm.

For the SLD-12, Sundown Audio relies on a robust motor design featuring two magnets and a bolted motor structure. The black 2.5-inch aluminum voice coil facilitates efficient heat dissipation, while the four-layer high-temperature copper winding is designed for high thermal endurance. Ventilation channels in the pole piece, along with additional cooling vents near the upper pole plate, aid heat dissipation and reduce airflow noise.

The specially shaped diaphragm design is engineered to ensure the quietest possible movement, even at larger strokes. With a linear Xmax of 12 mm, the SLD-12 offers sufficient stroke for powerful bass reproduction despite its flat design. Sewn “Mini-XL” leads further enhance mechanical reliability under heavy use.

The SLD-12 is available either as a D2 (2 × 2 ohms) or as a D4 (2 × 4 ohms), allowing it to be flexibly adapted to different amplifier and system configurations.

Technical Specifications – General

• Subwoofer size: 12 inches / 30 cm
• Type: Shallow-Mount Subwoofer
• RMS Power Handling: 600 watts
• Peak power handling: 1,200 watts
• Voice coil: 2.5 inches
• Voice coil former: Aluminum
• Voice coil winding: 4-layer high-temperature copper wire
• Voice coil options: D2 or D4
• D2: 2 × 2 ohms
• D4: 2 × 4 ohms
• Xmax: 12 mm
• Diaphragm area Sd: 735.5 cm²
• Dual-Magnet Motor System
• Ventilated magnetic gap
• Cooling channels in the pole core
• Magnetic short-circuit ring for optimizing the drive
• Sewn "Mini-XL" Voice Coil Leads
• Bolted Motor Assembly
• Specially shaped diaphragm for reducing mechanical noise
  
  

Thiele-Small Parameters – SLD-12 D2

• Voice coil: Dual 2 ohms
• Re: 3.65 ohms
• Fs: 42.96 Hz
• Qms: 2.227
• Qes: 0.691
• Qts: 0.415
• Capacity: 26.89 liters
• Mms: 204.32 g
• Cms: 67.18 µm/N
• Area: 735.5 cm²
• BL: 19,868 Tm
• Efficiency: 88.1 dB
• Xmax: 12 mm
• RMS Power Handling: 600 watts
• Peak power handling: 1,200 watts
  
  

Thiele-Small Parameters – SLD-12 D4

• Voice coil: Dual 4 ohms
• Re: 6.85 ohms
• Fs: 45.14 Hz
• Qms: 2.298
• Qes: 0.619
• Qts: 0.487
• Capacity: 29.48 liters
• MMS: 168.77 g
• Cms: 73.65 µm/N
• Area: 735.5 cm²
• BL: 23.025 Tm
• Efficiency: 88.3 dB
• Xmax: 12 mm
• RMS Power Handling: 600 watts
• Peak power handling: 1,200 watts
  
  

Dimensions

• Outer diameter: 12.625 inches / approx. 320.7 mm
• Installation diameter: 11.125 inches / approx. 282.6 mm
• Installation depth: 5.45 inches / approx. 138.4 mm
• Motor diameter: 7.4 inches / approx. 188.0 mm
• Subwoofer displacement: 0.07 ft³ / approx. 1.98 liters
  
  

Case Recommendations

• Sealed enclosure: 1.0 ft³ / approx. 28.3 liters
• Bass-reflex enclosure: 1.5 ft³ / approx. 42.5 liters
• Recommended bass-reflex tuning: 35 Hz
• Recommended port area: 20 in² / approx. 129 cm²
  
  

4th-Order Bandpass Recommendation

• Sealed chamber: 0.75 ft³ / approx. 21.2 liters
• Ventilated chamber: 2.25 ft³ / approx. 63.7 liters
• Port area: 45 in² / approx. 290 cm²
• Port length: 6 inches / approx. 152 mm
  
  

The Sundown Audio SLD-12 is particularly well-suited for installations with limited mounting depth and combines a space-saving shallow design with high power handling and a remarkable cone excursion for this form factor. This makes it an attractive solution for compact, high-performance subwoofer enclosures in vehicles
.