Acoustic Research AR-3a Loudspeaker Pair, Oiled-Walnut Cabinets, SN 62616 & 62621, June 23, 1972, Exceptional, Mint Condition. These were ordered in conjunction with an AR Amplifier and other equipment specifically for accurate, high-fidelity playback of choir music and voices. This system was installed with the speakers completely protected and mounted in special enclosures slightly above head level that were flush with the wall surface. Magazine (Julian Hirsch) contacted AR to borrow a pair of mint-condition AR-3a speakers to compare with the upcoming review of the new AR-303 (the AR-303 was intended to be a modern-day replica of the original AR-3a). A complete test report was published in the June, 1995 issue of. The differences in those two speakers is shown on a series of response graphs which will accompany the sale of these speakers. A copy of the test review and the frequency-response graphs and measurements will be made available to the purchaser of these speakers. These AR-3a speakers are highly collectible and in exceptional, mint condition, both physically and electro-mechanically. There are no issues, and the all drivers work exactly as when new without having to move the level controls back and forth. These speakers have been carefully tested and perform well. No modifications have been made to these speakers and they are completely original. The original beige-linen grills are nearly perfect without any sign of deterioration or “dust” lines or fading of any type, and the logos are in new condition. The oiled-walnut cabinets are in flawless condition without any scratches, nicks or marks. These speakers have been used very little during the first two years, and they were used in the. Test and then put into air-conditioned storage from 1994 until 2016. AR-3a 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 new dome midrange and tweeter drivers, based on the original AR-3. The AR-3a was designed by Chuck McShane and Roy Allison of Acoustic Research, Inc. And the speaker was introduced at the New York High Fidelity Music Show in October, 1967. Edgar Villchur, with the objective of improving the already stellar off-axis dispersion of the renowned AR-3. 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 acoustically sealed, heavily braced (nine internal braces screwed-and-glued to the inside of the cabinet) and critically 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 a/s 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 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 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% efficient (84-85 dB), meaning that a stable 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, is 54 lbs. Overall Description covered by. Reproduction or copying of any of this material without the express permission of the writer is unlawful and prohibited. The item “Acoustic Research AR-3a Loudspeakers OW, SN 62616 & 62621, Exceptional, Mint” is in sale since Monday, May 30, 2016. This item is in the category “Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Speakers”. The seller is “acoustic-research-inc” and is located in High Point, North Carolina. This item can be shipped worldwide.
- Brand: Acoustic Research, Inc. (“AR”)
- Model: AR-3a
- Country//Region of Manufacture: United States