1-Inch(25mm) Silk/Polymer Composite Dynamic Balance Dome Tweeters with powerful Neodymium magnet structure delivers clear and detailed high frequency response for realistic reproduction of vocals and instruments. Dynamic Balance Composite Drivers are lightweight and stiff with good damping for high efficiency excellent bass and lower distortion. Multiple small-diameter driver design delivers a more open "box-less three-dimensional sound. Critically Tuned Flared Ports minimize port noise ("chuffing) for good low frequency extension resulting in natural full-bodied sound with rich bass. Non-resonant all-MDF enclosure construction with 3/4 inch thick baffles ensures cleaner clearer more lifelike sound quality. Tower models feature additional front-to-back and side-to-side internal bracing. Computer modeled anti-diffraction grilles. Narrow baffle profiles create superior three-dimensional imaging and sound stage. Dual Five-Way Binding Post Connectors for more secure hook-up options and bi-wiring and bi-amping flexibility. High efficiency design enables the TSi Series to reveal the classic Polk Audio sound (open spacious and clear) even when driven by modestly-powered amplifiers and receivers.