The TS-W311D4 utilizes a highly rigid, fully-enclosed, single piece Basket, derived from our world-record holding SPL competition subwoofer, to help minimize the vibration throughout the subwoofer and increase the driving force to the cone, producing louder and rhythmical bass. Improved stiffness of the Basket provides for less sound leaks creating more clear and powerful bass. Pioneer’s imp composite cone is newly re-designed to deliver a durable cone structure for Accurate, yet powerful bass. The subwoofer now provides a single piece cone and drive cone, in addition to a lightweight and rigid dust cap. This combination offers more rigidity throughout the cone Versus competitors in its class. An extremely durable, yet lightweight cone is vital to prevent cone failure at high sound pressure levels. With the TS-W311D4, engineers re-designed the Spider assembly to allow the subwoofer to produce more Accurate and rich bass. Taking notes from our high-end SPL competition and reference Series speakers, the Spider is now assembled onto the Spider Holder rather than directly on to the Basket. Since the cone is also assembled onto the Basket which can cause additional vibration, the independent structure of the Spider Holder helps minimize vibration coming from the cone. This improves playback response, sound outline, and provides high linearity.