All three Uni-Fi loudspeakers, bookshelf, floorstanding and center-channel, employ a concentric driver. Because of its ideal time-domain characteristics, a concentric design, combining a tweeter and midrange diaphragm within a single voice coil, delivers the most coherent and accurate reproduction across the treble and midrange frequency spectrums. Because of their high cost, concentric drivers are traditionally used in only the most expensive speakers.