Polk Audio AM3365-A TL3 Center Channel Speaker (Black) The ring radiator tweeter, a tweeter that has never been used in a compact loudspeaker before; it produces incredible accuracy and detail (beyond even 30kHz!) Time Lens technology aligns the acoustic centers of the tweeter and mid-bass driver on the same spatial plane for superior imaging, while an acoustic lens incorporated in the grille smoothest the tweeter's frequency response The drivers used in the Blackstone TL Series can move farther, more smoothly, in a smaller space than any other speaker driver in an enclosure this size, achieving the kind of dynamic response (clarity, volume) you'd expect from much larger speakers