Neumann KM64
A small-diaphragm Neumann condenser that shows up in studio gear lists far more often than in spec sheets.
Overview
Working engineers recognize the KM64 instantly and collectors argue about it endlessly. Solid documentation is thin, and the microphone turns up in odd places: the mic locker of an Austin project studio, the fine print of a 1980s classified ad, a package deal stacked four-deep. What the record does establish is that it belongs to the KM-series family of small-diaphragm condensers. It was also desirable enough by the late 1970s and early 1980s that studios and dealers were actively hunting for used examples.
One snapshot comes from a studio profile in EQ (date and page not confirmed in available sources). It listed a Neumann U47, a KM64, and a pair of KM54s among the microphones at Bismeaux Studio in Austin, Texas - Ray Benson's room. That's a working studio's working locker, not a museum shelf. A second EQ studio profile from the same era placed a KM64 in the mic collection at Private Studios in Urbana, Illinois, alongside a U47, SM23C, and multiple KM56s. Two independent professional facilities both kept one.
The classifieds tell a parallel story. Throughout 1980, a recurring "Want To Buy" notice in the Broadcast Equipment Exchange - placed by J. Mandel of Triton Productions in Brighton, Massachusetts - listed the KM64 in a long want-list of Neumann models that also included the KM53, KM54, KM56, KM63, KM66, KM84, KM86, and U87. The same notice ran month after month in slightly different forms. Somebody wanted KM64s badly enough to keep asking. By 1996, a Mix (January 1996, p.222) equipment-for-sale listing offered four KM64s described as "perfect/10 of 10's" alongside a pair of U47s, a pair of KM56s, and three KM53s.
The technical documentation runs dry here. The available sources confirm the model name, its place in the KM-series, and its standing among engineers. They do not give capsule type, diaphragm material, frequency response, sensitivity, impedance, connector, or powering requirements. The KM-series as a whole was a small-diaphragm condenser line, and a 1980 Recording-Engineer (February 1980, p.88) feature on the KM50 series discusses the engineering pressures of shrinking capsule diameter while holding the noise floor down. Whether the KM64 shares the KM56's capsule lineage or takes a different path is not established in the sources at hand, so don't assume. The model number sits between the KM63 and KM66 in Neumann's naming, but the sources do not spell out what that implies about the circuit or capsule.
Owners and studios report the KM64 as a microphone worth chasing and worth keeping. Its reputation is better documented than its specifications. Anyone buying one should check the capsule and circuit against the actual unit in hand, because the data sheet, at least in the material available here, does not exist in reliable form.
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