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RCA BK 1 A 'the Ice Cone'




The RCA BK 1 A non-directional (dynamic omni)pressure microphone saw the light in 1952 as successor of the RCA 88 A, and was meant for broadcast use in AM and FM radio, and for use in television studios for speech and music. It was named 'the Commentator' by RCA, but it was the nickname 'Ice (Cream) Cone' that stuck.

If used vertically it was non-directional. Tilted horizontally, it was semi-directional. The design was totally new and radically different; all other microphones were radial (side-addressed), but the BK 1 A was axial; it could be pointed at the sound source, one had to speak into the top.

This design was nothing less than a break-through and is now used by all microphone manufacturers, for almost all modern microphones.

The 'Ice Cone' was not limited to the studio, but well-suited for outdoor use, as the construction eliminated the effect of air currents. Because it was also uninfluenced by handling and mechanical vibration, it was ideal for reporters.

The sleek and unobtrusive BK 1 A could be seen on many TV reporter desks, and was used by the US Presidents Truman, Eisenhower, Kennedy and Johnson for official speeches. The microphone was produced until at least 1969, when the competition came up with smaller designs better suited to the era. RCA did not present a successor and instead ended all production of microphones in 1973.

This is one of the types that feature in my book Witnesses of Words, which was recently released. More information about that can be found at

wow cover



RCA BK 1A ad