MTX 95, 75, S65, 55, and 35 Series subwoofers include Progressive Suspension technology that allows them to reduce distortion at high volumes resulting in cleaner, better sounding bass. A typical subwoofer suspension, the spider, is constructed of some material like poly-cotton or nomex that helps control the movement of the subwoofer while it is playing. A traditional spider consists of peaks that are have the same amplitude across the entire suspension, while the new MTX progressive suspension has peaks that are larger at the edge of the subwoofer and shorter closer to the voice coil. This "progressive" design allows the spider to better control the movement of the subwoofer and match the progressive qualities of the surround. At high volumes this reduces distortion that can be created during these times of intense movement. Additionally the 95 and 75 models take the technology one step further using a progressive poly-cotton foam sandwich suspension that requires no "break-in" period so you can start enjoying these subwoofers at whatever volume you prefer as soon as you get them installed.