Bang & Olufsen Beovox M-70 (c. 1976–1978)
The Beovox M-70 was Bang & Olufsen's phase-coherent loudspeaker of the mid-1970s, sold under the "Uni-Phase" name. High Fidelity (February 1976, p.67) reviewed it as a floor-standing system on a matching stand at $700 per pair. The magazine used it to explain what phase distortion does to the sound - a blurred sound picture and poor instrument localization, most noticeable in the lower midrange. The M-70's driver arrangement was designed to correct the amplitude and phase shifts that cause that smear.
By the time Audio (May 1978, p.66) tested it, the price had risen to $790 per pair. Audio's spec sheet lists a three-way system with a 10-inch (25 cm) woofer, a 5.75 cm midrange and a 1-inch (2.5 cm) tweeter. It covers 38-20,000 Hz ±4 dB into 4 ohms and is rated for 100 watts of music power. Each cabinet weighs 55 lb (25 kg) and shipped with a detachable 14-foot cable.
The two reviews don't quite agree on cabinet dimensions. High Fidelity measured the front panel at 25¾ × 12¾ inches, 10 inches deep, with the stand bringing overall height to 39½ inches. Audio gave 35 × 65 × 29 cm. Both agree the U.S. distributor was Bang & Olufsen of America in Elk Grove Village, Illinois, and that a one-year warranty backed it.
Beyond those period reviews, documentation is thin. Production years, total run and later collector-market history aren't recorded in the archive.
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