Acoustic Research AR 303 loudspeaker

It's a common audiophile failing to remember the past as being much better than it actually was. (Though, of course, some things were better.) I remember the first time I heard a pair of Acoustic Research LST loudspeakers, in 1974 or thereabouts. Compared with the Wharfedales I used in my own system and the various Goodmans, Celestions, and home-brews I heard at friends' homes, the sound of classical orchestral recordings on the ARs was about as close to the real thing as I could imagine. And the AR ads reinforced my experience, telling me that musicians such as Herbert von Karajan also used LSTs. I never heard those speakers again, but occasionally I wonder how they would hold up today (footnote 1).

The trapezoidal LST was AR's top model back then, featuring quadruple ¾" dome tweeters and 1.5" dome midrange units with a single 12" woofer in a sealed enclosure. The more conventional AR-3a, designed by Roy Allison and introduced in 1967, was a more conventional three-way design, using the same woofer with just one each of the dome midrange and HF units. Its mellow balance pioneered the cerebral "East Coast" sound in the '60s. I never heard the AR-3a, but I've heard audiophiles proclaiming it still to be one of the best speakers of all time. It was also, by all accounts, an amplifier-killer, its impedance featuring a punishing combination of low magnitude and high phase angle!

Acoustic Research—or AR, as it nowadays prefers to be known—has been through some turbulent times since the early '70s. Sold by its founders to the Teledyne conglomerate, the company never quite seemed to know who its customers were. Perhaps reflecting the schizophrenic nature of its name, some Acoustic Research models, such as the Tim Holl-designed AR 9 of 1979 and the Ken Kantor-designed MGC-1 of 1984, were aimed fairly and squarely at high-end customers. Yet much of the AR line seemed intended to compete head-on with the value-for-money offerings from Polk and Boston Acoustics.

The company's fortunes slipped through the '80s. In 1990, it was sold to International Jensen, who formed a new "Specialty Audio Group" in late 1993 to manage the Acoustic Research, Now Hear This, Day-Sequerra, and Audio Innovations brand names. After nearly 40 years in Massachusetts, Acoustic Research's marketing and engineering offices' design efforts were relocated to the NHT headquarters in Benicia, California, with design efforts coordinated by NHT's founding engineer, Ken Kantor, and management in the hands of NHT's other founder, Chris Byrne. [The brand was purchased by Recoton at the end of 1990s, and was sold to Audiovox in approximately 2003.—Ed.].

Given this history, when AR offered their new top-of-the-line loudspeaker, the 303, for review, I didn't need to be asked a second time.

Design
The $1200/pair 303 is Ken Kantor's re-engineering of the 3a. Similarly sized and similarly heavy but more expensive—at least in 1995 dollars—it uses what superficially appear to be the same drive-units: the hefty, long-throw, 12" woofer, the ¾" cloth-dome tweeter, and the 1.5" dome midrange driver with its distinctive metal-mesh protective cover. Rather than the 3a's rather haphazard placement, however, the 303 mounts these drivers in a vertical array, with the tweeter and midrange offset to one side of the baffle. (The speakers are supplied as a mirror-imaged pair.)

But the drive-units are not the same, having been redesigned in light of the development in technology in the 30-odd years since the originals were produced. The crossover frequencies are also slightly different, at 650Hz and 5.5kHz compared with 600Hz and 5kHz. The crossover is carried on a small printed circuit board attached to the inside of the terminal panel, and uses a mixture of polarized and non-polarized electrolytic capacitors and ferrite-cored inductors as well as a bunch of power resistors. The woofer and midrange low-pass crossover slopes are second-order, 12dB/octave; the tweeter high-pass is third-order, 18dB/octave; and the midrange unit rolls in with a 6dB/octave electrical slope. Internal wiring appears to be 18-gauge and is attached to the drive-unit terminals with push-on clips.

Ken Kantor is the farthest thing from a tweak like me, so there's no provision for biwiring, nor are the speakers supplied with spikes or the bushes into which to screw them. The enclosure is made of 1" MDF covered with a black laminate material and completely stuffed with bonded acrylic fiber. At 54 lbs, the 303 is a solid chunk of speaker!



Footnote 1: The various Cello loudspeakers are direct descendants of the LST; designer Mark Levinson used the old AR model as his paradigm from which to go forward. In fact, the Cello Amati looked like a stacked pair of LSTs and used AR drive-units.—John Atkinson
Company Info
Acoustic Research
Division of Audiovox
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Comments
65DegN's picture
AR 3a

Regarding this statement; "...It was also, by all accounts, an amplifier-killer, its impedance featuring a punishing combination of low magnitude and high phase angle!..."

During a period in the early 1970's I ran a service center for a major audio distributor in northern Ohio called Bullet Distributing (Tokyo Shapiro). I never saw an amplifier get killed by an AR 3a. I owned a pair of 3a's myself and my amps never had any difficulty driving them. 

However what was an amp killer was the EPI (Epicure) line. These speakers dropped down to around 2.5 ~ 3 ohms at certain low frequencies and we were at times unindated with blown amps from these. I remember the Sherwood Darlington oputput amps were particularly popular but they kept tripping the protect relay when used with the EPI's. Their answer to this was to change the tripping point which resulted in a massive number of smoked output stages.

Salesmen in our company gave me grief because they wanted to sell these two in combination and I was telling my customers why their Sherwood amps were blowing up. I got called to the carpet for telling the truth.

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