Astatic DK-1

MoMics note:

The Astatic corporation were well known for their excellent piezoelectric crystal transducers, some of which are still valued today, particularly for their use as harp (harmonica) microphones. The crystal elements could tolerate blasts of air and moisture - they do not all last for half a century (or more) under such conditions, but many survive and are still working to this day.

The DK-1 was an elegant omnidirectional model with a tapered body and circular arrangemet of slots all around the body. The microphone is designed to be used pointing upwards, to pick up sound evenly from all directions, and would be ideal to record conversations in a room or to be placed in the middle of a group of musicians. The DK1 appears in numerous advertisements in catalogs from Lafayette and Radio Masters between 1951 and 1955, and we have dated it based on those ads.

From the 1952 Radio's Master Catalog (17th edition. page D-3)

"New non-directional unit for studio and public address, featuring reduced size and design established primarily to allow unobstructed, least detracting view of performer. Brushed chrome finish contributes to this purpose by reducing distracting light reflections and glare. Excellent frequency range, with rising characteristics between 2,000 and 5,000 c.p.s. Output level is approximately -55 (Crystal element has moisture-proof coating. Includes 10 ft. rubber covered, shielded single conductor cable. Available with off-on switch (SC-11) at $2.70 extra."

Astatic used the same body shape and probably the same casting moulds for their later omnidirectional dynamic model M-350. The dynamic models are painted black rather than being chrome plated.

The frequency chart below shows the response of this DK1 crystal microphone (red), compared with the similar looking M350 dynamic microphone (black).