Time Lens technology-The acoustic centers of the tweeter and mid-bass driver are located in the same plane for superior imaging, while the acoustic lens incorporated in the grille smoothes the tweeter's frequency response. The TL Series creates imaging and frequency balance previously impossible in small, high performance satellite speakers. TL1 satellite aperiodic-tuned rear port enables better blending with a subwoofer. This design combines the bass extension of an acoustic suspension enclosure with the mid-bass boost of a ported enclosure by controlling airflow through the port for better extension without distortion. Curved enclosure design employs non-parallel surfaces that not only lead to a stronger, more rigid and acoustically inert enclosure, but they also result in less audible coloration from internal surface resonances. 1/2 silk dome tweeter for crisp, clear imaging and smooth response that's never tiring. 2-1/2 long-throw driver with Dynamic Balance driver technology-Polk's patented transducer design process scientifically tunes materials to produce a flat frequency response, with sharp detail, transparency and the ability to play loud without strain.