Acoustic Research AR-3a “Cutaway” Display Loudspeaker, Special Unit (One Speaker) For Display. Extremely Rare, Last One. AR-3a “Cutaway” Loudspeaker Display Speaker. This one-of-a-kind AR-3a “Cutaway” from Acoustic Research was a show-demonstration version of the AR-3a, hand-made by AR craftsmen in the late winter of 1967 for trade shows and the AR Music Room. Three “Cutaways” were originally fabricated by hand, and the other two were dismantled by AR and destroyed. This last speaker, and original AR-3a prototype, belonged to Delrama International of 1140 Broadway, New York, New York, and was actually one of the AR-3a Prototypes, as noted by the non-painted midrange and tweeter front plates. This last “Cutaway, ” no serial number assigned, was to be displayed in Italy, Germany, France, United Kingdom, Asia and other parts of the world. This “Cutaway” has functioning drivers, but the midrange and tweeter were disconnected with only the woofer in operation, and an audio oscillator, Hewlett-Packard Model 200CD, was used with a power amplifier to allow the Alnico 12-inch AR woofer to pump back and forth at around 5 Hz so audiophiles could observe the operation of an Acoustic Research acoustic-suspension woofer system, considered by many experts through the years to be the finest ever designed for low-distortion bass response. This AR-3a “Cutaway” is in perfect, original condition, and it has been packed in its original carton for nearly thirty years and displayed only once during that time for the October, 1994 AR 40. Birthday Party on the east balcony of Grand Central Terminal in New York City. This is a very special Acoustic Research loudspeaker and would make a unique and very special “center piece” to a large AR speaker collection. The Acoustic Research AR-3a Loudspeaker. 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 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. The result was a speaker containing one of the widest and most uniform midrange and treble dispersion of any forward-facing loudspeaker ever designed for home sound reproduction. 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 much 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 ten-times higher 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, meaning that an amplifier capable of at least 30-50 watts-per-channel into 4 ohms is the minimum suitable power. 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 Cutaway Display Speaker, Special Unit, Extremely Rare” is in sale since Tuesday, November 12, 2019. 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.
- Amplifier/Oscillator: No Amplifier or Oscillator supplied
- Model: AR-3a “Cutaway” Display Loudspeaker
- Modified Item: Yes
- Country/Region of Manufacture: United States
- Custom Bundle: Yes
- California Prop 65 Warning: N/A
- MPN: AR-3a “Cutaway” Display Loudspeaker
- Modification Description: Acoustic Research specially modified “cutaway” display speaker for display purposes
- Brand: Acoustic Research, Inc (“AR”)
- Shipping Carton: Special “box-within-a-box” Carton
- Bundle Description: This is a special product for display purposes.