This is a pair of Acoustic Research Ar-3A Loud Speakers that are unmolested. They are working great, but one nob you have to play with, it needs slight adjustment. These speakers are in excellent condition. They are listed in my store. You can pick them up or I think they would have to be freighted. Here is some info that I found on them. AR-3a History, Performance and Physical Description. The AR-3a is a 3-way, full-range, 4-ohm acoustic-suspension loudspeakertechnically a bookshelf speaker for very sturdy bookshelveswhich. Includes the well-known AR 12-inch acoustic-suspension woofer and 1-1/2-inch dome midrange and 3/4-inch dome tweeter drivers, based on the original AR-3. The AR-3a was primarily designed primarily by Roy Allison and. Chuck McShane of Acoustic Research, Inc. And the speaker was introduced at the New York High Fidelity Music Show in October, 1967. The result was a speaker with the widest dispersion of any forward-facing loudspeaker ever designed until the Allison: One was introduced in mid-1970s. The question of whether the AR-3a was superior or more accurate than the AR-3 has always been asked, and in many ways. Speaker can outpoint the other; however, the AR-3a was an improvement in off-axis dispersion of all of the drivers by the new lower woofer crossover and the smaller dome tweeters used. The acoustically sealed, heavily braced (nine internal braces screwed and glued to the inside of the cabinet) and properly damped (the “Q” of the AR-3a is 0.9 – 1.0) AR-3a enclosure volume is 1.7 cu. Which is optimal for the 41-43 Hz resonance frequency, and the woofer’s suspension restoring force ratio is approximately 85% acoustic and 15% mechanical, far greater than nearly all current consumer loudspeakers using the acoustic-suspension design. For this reasonand the basic design of the motor system in the AR wooferthe AR-3a has. Lower harmonic distortion than any conventional, current-design loudspeaker of a comparable size. Julian Hirsch measured the woofer’s harmonic distortion at a power level. Than usual, customary test input voltages, and the distortion in the AR-3a’s woofer was under 9% at 20 Hz, setting a new standard of low distortion, especially at this high-power testing. The woofer used in this pair of AR-3a speakers has a large 9.6 lb Alnico-5 magnet assembly, cast-aluminum frame and a long-throw, 2-inch heavy-duty copper voice coil with a linear excursion of 5/8-inch and a maximum physical excursion of 1.2 inches. The midrange driver has a 1½-inch treated-cloth dome (hemispherical) diap. Gm with 1½-inch copper voice coil on an aluminum former assembly. The midrange driver is critically damped with fiberglass pads under and above the dome assembly itself. The magnet assembly is a large ferrite unit. The AR-3a tweeter uses a ¾-inch treated-paper dome diap. Gmsimilar to the original AR-3 phenolic-dome tweetersuspended. By urethane-polymer foam pieces in the outside portion of the voice coil with a layer of clear butyl-rubber sealing the outside of the magnetic gap. The magnet assembly is ferrite. The drivers have LCR crossover frequencies of 575 Hz and 5,000 Hz. The speaker’s impedance ranges from 2.7 4.9 ohms, and the speaker is approximately 0.5-0.7% efficient, meaning that an amplifier capable of at least 30-50 watts-per-channel into 4 ohms is the. The AR-3a physical dimensions are 14 x 25 x 11-3/8. The AR-3as net weight, each, unboxed, is 54 lbs. The item “Acoustic Research AR-3a Loudspeaker Pr Oiled-Walnut SN 30728 & 37199 Unmolested” is in sale since Monday, January 23, 2017. This item is in the category “Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Speakers”. The seller is “llucas676902fj” and is located in Merrillville, Indiana. This item can be shipped to United States.
- Brand: Acoustic Research (“AR”)
- MPN: AR-3a
- Model: Acoustic Research AR-3a
- Country/Region of Manufacture: United States