Aramid Fiber Interlaced Injection Molded Polypropylene (IMPP) Cone Construction Butyl Rubber Surround for Strength and Linearity During High Excursion Oversized 56.4 oz Double Stacked Magnet and Vented Pole Yoke for Increased Power Handling D Subwoofer, FORCEFUL, DEEP, DEFINED. Too much isn't enough, embrace the bass. The D subwoofer is a culmination of Pioneer technologies that produce thick, deep, powerful and accurate bass that makes listening to your favorite music energetic, fun and engaging. Combining bass quality and bass quantity with high power, plus installation flexibility that provide high performance in both acoustic suspension (sealed) and bass reflex (ported) enclosures, the D subwoofer is the ultimate all-around performer. Slam, attack, power. Don't just listen to your music, feel it. BUTYL RUBBER SURROUND Made of a specially blended, highly durable and moisture-resistant compound, butyl rubber keeps the cone moving in a linear direction, seals the cone to the basket and quickly dampens cone vibration once the signal has changed or stopped. This results in less distortion and superior frequency response. ARAMID FIBER INTERLACED INJECTION MOLDED POLYPROPYLENE (IMPP) Polypropylene (PP) is a tough thermoplastic resin that is an ideal material for a subwoofer cone - with low mass and high damping, PP cones offer good sensitivity and low distortion. However, polypropylene cones lack the rigidity and strength required for high output and extreme low bass. To resolve this, Pioneer engineers used advanced Computer-Aided Manufacturing to develop a process to blend aramid fibers into the polypropylene resin during the injection molding process. The resulting Aramid Fiber Interlaced IMPP subwoofer cone is incredibly strong and low mass with high rigidity and superior strength to produce deep, powerful and undistorted bass. LARGE DIAMETER VOICE COIL AND DOUBLE STACKED MAGNETS A subwoofer motor structure consists of the voice coil and magnet a