Acoustic Research Suspension Speaker Set (Bookshelf Speakers). The AR-4x has 2 1/2 cone tweeters and has received outstanding reviews and is remains famous for its sound quality. 2-way acoustic suspension speakers in beautiful walnut veneer with the typical white Acoustic Research cloth grills. The walnut veneer on one of the speaker cabinets has a chip. Speaker foam should probably be replaced. Drive units: 8 inch acoustic suspension woofer, 1 ΒΌ inch high-frequency cone. Impedance: 8 ohms nominal. Controls: High-frequency level adjustment. Amplifier: Up to 100 watts per channel. Size: 10 x 19 x 9 inches. Weight: 18.5 lbs. Woofer resonance: Free air 30 Hz, in enclosure 65 Hz. Volume of enclosure: 0.65 cu ft. The item “Vintage Acoustic Research Suspension Speakers AR-4x (Bookshelf Speakers)” is in sale since Wednesday, December 06, 2017. This item is in the category “Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Speakers”. The seller is “minidiscguru” and is located in Chicago, Illinois. This item can be shipped to United States.