Koss CM-1020 (advertised 1978–79)
Little is documented about the Koss CM-1020. Nearly everything in the Archive's record comes from Koss's own magazine advertising rather than independent reviews. The advertising does settle one thing: the CM-1020 was a loudspeaker, not one of the headphones Koss was better known for at the time.
The ad campaign was built around what Koss called its "Theory of loudspeaker design," a computerized approach the company contrasted with what it described as the trial-and-error methods common in the industry. In an advertisement that ran in High Fidelity (March 1978, p.48), Koss claimed the CM-1020's design delivered a 3 dB gain in electrical efficiency and a 3 dB down point of 31 Hz, with maximally flat response over the low bandpass. A version in HI-Fi-Stereo-Buyers (March 1979, p.7) added that the computerized theory helped make an "optimum 3-bandpass" speaker a reality. It described a performance-synthesized design meant to capture presence and musical energy from 300 Hz to 3.5 kHz.
Those are manufacturer marketing claims, not measured test results. No independent lab reports, confirmed production dates, or original prices surfaced in the Archive's research. The published specifications are Koss's own words, and the rest of the record is thin.
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