Alpine X-W12D4 12′′ (30 CM) SUBWOOFER (4Ω + 4Ω)Alpine introduces the all new X Series of high grade speakers, subwoofers, and amplifiers. These products have been engineered and tuned to create a perfect match for extraordinarily dynamic, realistic sound reproduction and a spatial sound impression. With Alpine X Series subwoofers, you get the top of Alpines subwoofer technology for massive and accurate bass output. These flagship subs have been engineered and tuned with the highest precision and