The 1400 Hz crossover frequency of the Klipsch KL-650-THX speaker verifies the frequency response and allows you to set superior bass. The dual 6.5-inch Cerametallic woofers of this Klipsch bookshelf speaker deliver dynamic bass output. Get clean and crisp highs with the 6- by 10-inch Tractrix horn tweeter of this Klipsch speaker. The 48 Hz - 20 kHz (+-) 3db frequency response of the Klipsch KL-650-THX speaker offers audible and balanced sound at all levels. The 97db @ 2.83 volts / 1 meter sensitivity of this Klipsch bookshelf speaker delivers low but incredible audio. With 8 ohms nominal impedance, this Klipsch speaker ensures loud and thunderous sound.