Acoustic Research AR 206 HO Bookshelf Speakers, Black, 4 Ohm. Sound & Look Very Nice. Your Amplifier must be able to drive 4-ohm speakers. Hese high-end Acoustic Research speakers will create clear reproduction of your favorite music with surprisingly deep bass clear mids & highs in nice looking Classic Black Ash Speaker cabinets. The cloth grille covers are in good condition; left one has a small hole above just above the logo. The speakers have real rubber surrounds, not foam, and are also in excellent condition. The cabinets have wear consistent with normal use with some very light surface scratches. Please see photos for detailed description. 30-100 watts per channel that is capable of driving 4. 6-1/2 Woofers High Polymer Laminate Cone & real rubber surrounds (Not Foam). Tweeter 1 Dome. Impedance 4 ohms. Frequency Response 60Hz to 26kHz, -3 db. These speakers sound really nice and once hooked up to your Receiver/Amp, these speakers will create clear reproduction of your favorite music with a very balanced response and surprisingly strong bass, with clear mids & highs. 14-1/8 inches high, 8-1/2 inches wide, 9 inches deep.