Acoustic Research AR 303 loudspeaker
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.
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