QSC's <b>GP118</b> and GP218 subwoofers offer a unique solution that addresses the requirements of digital motion picture soundtracks. Featuring high excursion, 18" low-frequency transducers mounted in ported enclosures, these systems extend response to the lowest audible frequency.</p><p>The <b>GP118</b>/GP218 are premium, highperformance, direct radiating 18-inch subwoofers for screen channel or surround channel low frequency extension. With an impressive combination of low frequency performance and musical accuracy, the <b>GP118</b> and GP218 are an ideal subwoofer companion to QSC's AcousticPerformance&trade; Series loudspeakers when used in high output immersive sound surround<br />applications. Cabinets can be placed on the floor, or suspended from the ceiling to avoid occupying floor seating space.</p><p>The <b>GP118</b> features a single 18-inch transducer that incorporates a double layer spider and triple roll surround for extended<br />and controlled excursion at extreme power. The GP218 features two of these same transducers. The 4" voice coil is wound on a fiberglass former to prevent deformation at high operating temperatures and is extensively vented to reduce power compression. An aluminum demodulating ring also further reduces distortion.</p><p>The <b>GP118</b> and GP218 enclosures are constructed of 18mm Baltic birch plywood with internal bracing to eliminate acoustic losses due to panel resonance while maintaining the enclosure's robustness. Built-in M10 threaded fittings allow the <b>GP118</b> and GP218 to be easily and<br />safely suspended (using installer provided hardware). Further contributions to cabinet rigidity include vent walls constructed of the<br />same plywood as the enclosure. Ample port area allows free movement of air resulting in minimal turbulence and port distortion.</p><p>Finishing the enclosure's aesthetic design, the transducer is protected by a 16-gauge, powder coated steel grille. The subwoofers can be stacked vertically using their interlocking feet and recess features machined into the enclosure's top panel.</p>