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A.R. Loudspeakers
(Early production)
Acoustic Research, Inc. ("AR") was founded in 1952 and incorporated on August 10, 1954 by Edgar Villchur (inventor, writer, audio-electronics researcher and teacher) and his student Henry Kloss. AR-1 In 1954, Acoustic Research introduced the small AR-1 bookshelf loudspeaker that used the acoustic suspension principle developed by the company co-founders. The acoustic-suspension woofer (or air suspension woofer) uses the elastic cushion of air within a sealed enclosure to provide the restoring force for the woofer diaphragm. This principle revolutionised the loudspeaker industry in the late fifties because it provides a way to design a small speaker system (instead the refrigerator sized cabinets previously used to get halfway decent bass) with effective and more linear low frequency response. It will results very clean reproduction of deep-bass tones by drivers with relatively small cones (e.g. smaller than 12-16 inches in diameter) not mounted in a horn or other increased coupling at low frequencies enclosure. The acoustic suspension enclosure has one disadvantage: it is less efficient as the conventional and more large speakers (which in the fifties were driven by 10-20 watts tube amplifiers). Instead of 10 or 20 Watts, this new loudspeakers needed a more powerful amplifier. The Model AR-1 was showed in September, 1954, at New York Audio Fair. The 12 woofer, designed and built by AR was coupled initially with 8 high frequencies driver produced by Altec and based on Western Electric design,. Both units were in a sealed 3/4-inch thick plywood cabinet filled with fiberglass. Lately the high frequencies driver was replaced by one cone driver for mid-high frequencies.
Dimensions: 25" x 14" x 11" Weight : 50 lbs The speakers should be used in horizontal position.
Almost contemporarily AR introduced the AR-1W (a woofer only speaker), intended to be used with a separate high frequency unit.
AR-1 speaker input ( I cant explain it)
AR-2 In 1957, AR introduced a smaller, less expensive, acoustic suspension system, the Model AR-2. The original AR2 was a 2-way using two 3.5" cone drivers for the mid-high frequencies. These were mounted in a plastic 'cup' located above the woofer. This cup angled the drivers slightly toward one another. One smaller diameter woofer (10) Dimensions: 24 x 13 ½ x 11 ½ The speakers should be used in horizontal position.
AR-3
In 1958 AR introduced the model AR-3, which used the AR-1s acoustic-suspension woofer in conjunction with the first commercially available hemispherical mid-frequency driver and high-frequency tweeter, the so-called dome tweeter. The AR-3's 2-inch dome mid-driver and 13/8-inch phenolic-dome tweeter were the first direct-radiator dome drivers commercial manufactured. Dome diaphragms had been previously used, but these diaphragms were always used with horn-type and compression drivers, never as direct-radiator, wide-dispersion dome tweeters.
Dimensions: 25 x 14 x 11 The speakers may be used in horizontal or upright position.
AR-2A
A bit later than AR-3 (1959), Acoustic Research introduced the AR-2A. The AR-2a added the AR-3 tweeter to the existing AR-2 system.
The AR-2A technical specifications are available on request.
AR-3 ST (1958) Supertweeter only to add to the AR-3 or AR-2A speakers. It converts an AR-2 to the equivalent of an AR-2A or can be used to extend the high frequency range of an AR-1 (from the original AR advertisement) Dimensions : 11 ½ x 6 ½ x 5 1/8"
AR-3 T (1958)
This is the tweeter system of the AR-3 (mid-range and super-tweeter). It converts an AR-1 or an AR-1W to the equivalent of an AR-3. (from the AR original advertisement) Dimensions : 14 x 7 7/8 x 6 Ό It should be used in horizontal position.
AR-4 (1964)
In 1964 AR introduced this small two-way loudspeaker with an 8" woofer and small cone tweeter (3.5). Dimensions: 19 x 10 ½ x 9 ½
AR-4X Introduced in 1965, this loudspeaker has the same 8 woofer but a smaller cone tweeter (2.5), crossed very low [1200 Hz], so failures are common. The tweeter level of AR-4xs is controlled by a single continuous knob on the back of each speaker. The potentiometers tend to corrode over time, eventually silencing the tweeters, although the tweeters are in working order. Dimensions : 19 x 10 ½ x 9 ½
AR-3 A The AR-3 was later (1967) replaced by the AR-3A, with 1.5 dome midrange and a dome tweeter reduced in dimensions (1), for better mid and high frequency dispersion. It has too different crossover point (IIRC about 450 Hz). AR-3 and AR-3A have the same woofer (12) in the same sized box. Successively the tweeter was changed from the earlier 1 hard coated fabric dome to a .75 pressed paper dome. Dimensions : 14 wide, 11.5 deep, 25 tall and weigh approximately 53 pounds. The speakers should be used in upright position.
Schematics, specifications and original AR-3A brochures are available on request.
AR-2AX (1969) The dual mid-tweeters of the AR-2A were replaced with a single mid-frequency unit (3.5 cone). The tweeter was upgraded to the improved .75" paper dome tweeter. In early 2ax's were used the same "pot magnet" 10 woofer as the later 2a's, but this was successively replaced with a square ceramic magnet woofer of the same dimension that would serve in many AR models through the 70's and 80's. The cone of this new woofer was lighter and stiffer, with much stronger midrange output. Two 3 ohm resistors were wired in series with the mid-tweeter unit, to compensate for the change. Cross-over frequencies : 1400 Hz, 5000 Hz Dimensions : 24 x 13.5 x 11,5
High and mid controls.
AR-5 (1968 or 1969) 10 woofer, 1.5 mid dome driver and 0.745 dome tweeter. Midrange and tweeter units are identical in performance characteristics to those of the AR-3A. (from AR original brochure). Dimensions: 24 x 13.5 x 11.5
AR-2X (1970) Two-way speaker like his predecessor AR-2.It has 10 woofer with treated cloth surround and 2.5 cone mid-high frequency unit. Dimensions : 24 x 13.5 x 11.5
(Sorry, no pictures are available) |
From the original AR-1 advertisement
AR-1 bookshelf loudspeaker (1954)
AR-3 Schematics and original brochures are available on request.
Left: Early version (2.5 cone tweeter). Right: later version (2 cone tweeter)
LINK
http://totalaudio.tistory.com/entry/Acoustic-Reserch-AR-스피커의-분류와-역사-그리고-시리즈별-형태모습들 (AR-4X early, middle-age and late version)
The AR-2AX schematics are available on request.
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A.R. early models
Model |
Introd. |
Ways |
Woofer |
Mid-high |
Midrange |
Tweeter |
Dimensions |
Weight (Lbs) |
AR-1 |
1954 |
2 |
12 |
Altec 8 driver A.R. cone |
|
|
25 x 14 x 11 |
50 |
AR-1W |
1955 |
1 |
12 |
|
|
|
|
|
AR-2 |
1957 |
2 |
10 |
Two 5 cone |
|
|
24 x 13.5 x 11.5 |
|
AR-3 |
1958 |
3 |
12 * |
|
2 dome |
1 3/8 dome |
25 x 14 x 11.5 |
52 |
AR-3ST |
1958 |
1 |
|
|
|
Super-tweeter |
11.5 x 6.5 x 5 1/8 |
|
AR-3T |
1958 |
2 |
|
|
dome |
dome |
14 x 7 7/8 x 6 Ό |
|
AR-2A |
1959 |
3 |
10 |
|
Two 5 cone |
1 3/8 dome |
24 x 13.5 x 11.5 |
36 |
AR-4 |
1964 |
2 |
8 |
3.5 cone |
|
|
19 x 10.5 x 9.5 |
16 |
AR-4X |
1965 |
2 |
8 |
2.5 cone |
|
|
19 x 10.5 x 9.5 |
18.5 |
AR-3A |
1967 |
3 |
12 * |
|
1.5 dome |
1 dome 0.75 dome |
25 x 14 x 11.5 |
53 |
AR-5 |
1968 |
3 |
10 |
|
1.5 dome |
0.75 dome |
24 x 13.5 x 11.5 |
39 |
AR-2AX |
1969 |
3 |
10 |
|
3.5 cone |
0.75 dome |
24 x 13.5 x 11.5 |
36 |
AR-2X |
1970 |
2 |
10 |
2.5 cone |
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|
24 x 13.5 x 11.5 |
33 |
* In AR-3 and AR-3A series AR called the woofer a 12", but its really a unique 11" size all its own.
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