The Polk Audio RTiA9 High Performance Floorstanding Loudspeaker (Single, Black) features Dynamic Balance transducers - three 7 inch bass drivers, two 5.25 inch midrange drivers and a 1 inch high frequency dome tweeter - the RTiA9 will fill even the largest room with energy and excitement. With a mind blowing 500 W power capacity, watch high octane action movies in their full grandeur or delight in an intimate jazz performance. The proprietary curved, 6-layer DAHLI enclosure design creates the optimal shear damping for a more rigid, acoustically inert enclosure and minimal cabinet resonances. The RTiA7 cabinet is designed for clean, accurate sound. The two 5.25 inch midrange drivers are housed in their own tuned internal enclosures for increased clarity and lifelike detail. The RTiA9 Cascade Tapered Crossover eliminates the comb filtering and beaming, common to multi-driver speaker, which degrades the quality of the audio and collapses the soundstage. Klippel motor optimization uses laser measurement technology to ensure a smooth excursion path at either end of the volume spectrum for uniform performance at both low and high volumes. The Polk's proprietary, patented Dynamic Balance technology allows engineers to design out distortion-causing driver and system resonances, so you only hear the good sounds. Durable, computer-modeled, injection-molded butyl rubber surrounds suppress unwanted cone resonances for a lifetime of reliable sound.