1928 Neumann CMV3 Condenser Microphone

Microphones were and always will be the most loved legacy of Georg Neumann. The story starts more than a century ago.
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Microphones were and always will be the most loved legacy of Georg Neumann. The story starts more than a century ago. Born in 1898 in a small town outside of Berlin, Neumann apprenticed at Mix & Genest and did amplifier research for AEG. When AEG lab director Eugen Reisz created his own company, Neumann joined him and looked into ways to improve carbon microphone technology. Neumann stretched a tight rubber membrane over a marble slab containing powdered carbon and two electrodes. The resulting “Reisz marble block microphone” was fairly flat from 50 to 1k Hz, with a 10dB peak at 4 kHz, and was -15 dB at 10 kHz. Hardly impressive by modern standards, this 1923 model encouraged Neumann to look at other ways to improve mic performance.

During that time , as radio gained popularity and record companies switched over to the “electrical recording process,” microphones suddenly became a major link in the audio chain. Excited by the idea of building capacitive (condenser) mics, Neumann left Reisz and, with Erich Rickmann, founded Georg Neumann & Co. in Berlin in November 1928. Later that year, Neumann debuted the CMV3—the first mass-produced condenser mic.

The CMV designation referred to "Condensator Mikrofon Verstärker" (condenser microphone amplifier) and the number three probably indicates that two earlier prototype versions existed. Nicknamed the “Bottle mic,” the CMV3 had an omnidirectional M1 capsule with large, gold-sputtered colloidan (later switched to PVC) diaphragms and RE084 triode-based tube electronics.

In 1932, Neumann unveiled the CMV3A, featuring interchangeable capsule heads, including a cardioid version of the famed M7, which was later adapted for use in the U47.

Neumann had a worldwide distribution deal with Telefunken, so models for broadcasting use or export outside Germany had Telefunken logos. The only difference between "Neumann" and "Telefunken" models were the name badges (and model numbers in the case of the CMV3) that were applied just before the mics were boxed for shipment. This practice continued on through the late-1950s, when Neumann finally established its own distribution in North America.

Click here to download/view the original Neumann/Telefunken CM3 brochure (in German).