Extreme Power Handling: The Sundown Audio M18 subwoofer delivers immense bass with 2000W RMS / 4000W Peak power handling, ensuring phenomenal performance for even the most demanding car audio systems. This 18-inch subwoofer provides industry-leading levels of low-distortion output. Revolutionary Mega-Roll Surround: Featuring Sundown’s custom-tooled Mega-Roll Surround and patented frame design, the M18 achieves an incredible 35mm one-way linear excursion. This allows for the lowest possible bass extension in various enclosures with minimal distortion. Advanced Thermal Management: Built for sustained high performance, the M18 includes a 3" diameter 4-Layer Round Wire Aluminum Voice Coil on a thick aluminum former. A high-velocity pole vent, heavily vented magnetic gap, and proprietary cast-aluminum frame-base venting system keep the coil temperature in check. Robust & Optimized Design: The M18 boasts a quad stacked 200mm (7.87”) diameter motor structure with a 20mm thick top-plate for efficient magnetic circuitry. Its durable construction is highlighted by an etched all-black backplate and special M-series magnet boot design. Versatile Enclosure Compatibility: While primarily optimized for 7.0 cu ft net ported enclosures (tuned to 32Hz with 112 sq in port area), the M-series uniquely excels in sealed (3.0 cu ft) and IB applications. This flexibility makes it a highly adaptable choice for diverse car audio systems. Sundown Audio M-Series M18D2 Subwoofer: High-Performance Bass The Sundown Audio M-Series M18D2 Subwoofer is an 18-inch subwoofer that redefines performance for its class. Designed for demanding car audio systems, the M-series delivers intense, high-fidelity bass with stellar low-frequency extension and low distortion. It combines advanced engineering with a unique aesthetic, featuring an Etched All Black Backplate and a special M-series magnet boot design. Extreme Power & Unmatched Excursion The M18 is built to dominate with robust, controlled power delivery: Power Handling: 2000 Watts RMS / 4000 Watts Peak power. Excursion: Achieves a full 35mm one-way linear excursion (Xmax) for deep, clean bass reproduction. Voice Coil: Features a custom-developed 3" diameter 4-Layer Round Wire Aluminum Voice Coil wound on a thick aluminum former for optimal winding density. Impedance: Dual 2 Ohm. Revolutionary Motor and Patented Design The M18's strong performance is due to its custom-tooled components and engineering: Frame: Utilizes custom-tooled and patented Mega series frames and the signature Mega-Roll surround. Motor: Features a Quad Stack Magnet Structure—a 200mm (7.87”) motor with an 88mm (3.46”) stack height and a 20mm thick top-plate for an incredibly efficient magnetic circuit. Suspension: Features Sundown's proprietary fully computer-optimized PG linear suspension, designed for the lowest possible bass extension. Low Distortion: An integrated magnet inner-diameter aluminum shorting ring ensures superior inductive distortion performance across the entire frequency range. Superior Thermal Management and Specs The M-series incorporates an advanced high-stroke coil ventilation system for reliability: Cooling mechanisms include a high-velocity pole vent and a proprietary high-velocity cast-aluminum frame-base venting system to actively manage coil temperature. Dimensions: Outside Diameter of 18.46" and Cutout Diameter of 16.68". Mounting Depth: Requires 14.05" of depth with only 0.25 cu.ft of displacement. T/S Specs (M18D2): Features a low Fs (28.567 Hz) and an ideal