HDX3's motor features a thick top plate, high motor force, and a tight gap for high-efficiency speaker design. A taller 4-spoke, cast aluminum frame makes room for a larger diameter spider for lower tuning and greater accuracy. The HDX3's taller and wider surround allows for even more precise excursion and new pulp-blend cones are stronger than previous fiberglass-laminate designs- And they're lighter too! We are ditching the stitching on the 1500 Watt Power Band. Other improvements over the HDC series subwoofers include the presence of a thicker, more robust aluminum former, as well as black anodizing.Double slit venting and a higher temperature resin are included for increased cooling abilities, enhanced performance, and a longer subwoofer life. 1500 Watt RMS, 4500 Watt Peak Power (Burps Only).