The 18SWS1000 is a high-power 18-inch subwoofer, designed for use in professional applications. It is specifically designed to reproduce the range of 36 to 150 Hz in a 6 to 7 cubic foot (170-200 liter) vented box. The 18SWS1000 is capable of handling up to 1000 watts RMS (NBR or 2,000 watts continuous program power). A bumped and undercut T-yoke assures a minimum of magnetic rectification (off-centering) and a compatible maximum displacement (Xlim). The extended pole ensure a correct magnetic flux distribution and improve the thermal dissipation the magnet circuit was optimized by finite element software. Special attention was given to the driver's behavior under mechanical overload conditions, meaning that all but the most severe abuse will be tolerated without failure. The 18SWS1000 employ a 4” (100mm) diameter 4-layer aluminum round wire voice-coil. This is wound on a fiberglass-composite former, twice the thickness of typical formers, to drive the moving assembly with great rigidity. The non-pressed-long-fiber-pulp cone has the necessary mass and stiffness to withstand the tremendous accelerating forces required and is precisely centered by two counter-balancing, distortion canceling, polyester-cotton-fiber spiders. A reinforced aluminum frame is highly effective in withstanding mechanical shocks and vibration. It also acts as a heat-sink for the motor, without removing energy from the loudspeakers intended magnetic gap. The aluminum frame includes six vents that allow air exchange between the spider and the top-plate. This helps to reduce topplate temperature, in turn cooling the voice-coil. The magnetic-circuit also employs a multi-cooling system (patent pending) consisting of a large diameter center hole, surrounded by six smaller holes that forces cool air across the voice-coil. These features insure an extremely efficient heat transfer from voice-coil to surroundings, resulting in very high thermal power handling.