Innovative Design The RTi A7 features the latest generation of Dynamic Balance(R) polymer composite drivers for smooth wide-range response with low distortion. The RTi A7 uses multiple long-throw 7-inch woofers to combine the wide dynamic range benefits of a single larger woofer with the tight punchy accurate bass response of small woofers. Combined wwith PowerPort Plus these multiple woofers deliver deep high-impact bass with speed and accuracy. 1-inch Silk/Polymer Dome Tweeter delivers smooth response and better detail. PowerPort(R) bass venting for superior clean low distortion bass that you can really feel. PowerPort vastly reduces chuffing or port noise and provides deeper more powerful lower distortion bass than could be realized with conventional ported or sealed designs of comparable size. Magnetic shielding for safe placement near video sources. Mylar bypass capacitors in the crossovers extend high frequency response and improve detail and transparency. Neodymium magnet low-viscosity ferro-fluid cooling and a heat sink on the back of the magnet create better power handling and reliability. Dual bi-ampable gold-plated 5-way binding post inputs (with wide holes for large-gauge bare wire connections) for the most secure connections and the most versatile wiring applications. Butyl rubber surrounds for high performance durability Acoustically inert stamped driver baskets. Floating anti-diffraction grilles minimize grille diffraction for spacious 3-dimensional imaging. All-MDF construction and asymmetric cabinet design Cabinet resonance can ruin the sound of an otherwise well-designed speaker. You don't want to hear your speaker cabinets humming along with the music you want to hear the uncolored sound launched by the drivers and tweeters. We take special pains to make sure that Polk speaker cabinets are resonance-free. Our new RTi A Series loudspeakers employ an asymmetric design composed of a six-layer laminate the process for which was specifically developed for Polk and which controls resonance and increases cabinet rigidty. All-MDF construction with massive asymmetric cabinet bracing ensures resonance-free enclosures for accurate sound. (Cutaway view of RTiA9 shown right bracing is similar on other RTi models) Adjustable leveling feet in an outrigger base to provide stability on any type of flooring. Real Wood finishes at vinyl prices. PowerPortPlus PowerPort Plus is an enhancement in Power Port technology. Power Port Plus uses two ports (one front one rear) and internal plates to further reduce air turbulence and increase bass efficiency. PPP allows even lower frequency tuning and lower turbulence for less noise and distortion and more big musical bass even at lifelike volume levels. This technology delivers performance that vastly exceeds conventionally ported speakers with bass that you truly feel as well as hear. Learn more about PowerPort(R) Plus.