Acoustic Research, Inc. (AR) 1-1/2 Dome, 4-ohm, AR-3a Midrange, #200010-1, Inoperative, for Repair. This AR-3a midrange 1-1/2-inch dome driver is inoperative and not working. This unit was a factory demonstrator for instructional purposes. The voice coil on this AR driver is likely intact, but no specific test has been made because there are no lead-out wires. Also, the domes suspension is not intact. This midrange driver had an inverse half-round suspension to center the dome, and that portion has been removed and would require a similar piece to center the dome. The dome does have the proper fiberglass under the dome and the small pad to go between the screen and the top of the dome for damping. Properly working, this dome midrange driver is one of the finest midrange drivers ever designed. This midrange dome driver, dating from 1968, was designed Roy Allison and Charles McShane of Acoustic Research, to be used in the AR-3a and later the AR-LST. The driver is a 1-1/2-inch butyl-rubber treated linen solf-dome diaphragm and provided extremely uniform, accurate sound reproduction and dispersion within its pass band. The magnet assembly is ferrite and approximately 6 lbs. Note that this tweeter will be shipped with a protective cup covering the dome to prevent shipping damage. Ref. AR-2301890