Built to bring the big surround sound theater experience into the comfort of your living room, the Polk Signature Seriescontinues in the Polk tradition of American HiFi. Featuring Hi-Res certification, Dynamic Balance driver design, Terylene tweeters, mica-reinforced polypropylene cones, precision cross-overs, an anti-diffraction magnetic grille, a non-resonant MDF cabinet and exclusive Power Port technology, you get elevated sound for movies, TV and music in a totally re-imagined design.Enjoy rich, clean, full-range sound for movies, TV and music with Polk__s new Dynamic Balance acoustic array.1x 1__ high-resolution Terylene tweeter for crystal clear high frequency response that perfectly reproduces the latest high resolution audio files.3x 6.5__ low distortion mica-reinforced polypropylene cones with four-layer voice coils for clean, clear bass, better linearity, and dynamic mid-range.Exclusive Polk Power Port technology for greater, more impactful bass.Midrange driver: 3x 6.5 (16.51 cm)Tweeter: 1" (2.54 cm) Total Frequency Response: 36 Hz - 40 HzSensitivity (1W@1m): 90dB Nominal Impedance: 8 OhmRecommended Amplifier Power: 20 - 300 W (per channel)