CMV 3

Common name: Neumann CMV3

Production Status: Discontinued / Vintage

The CMV 3 is the first condenser microphone engineered and manufactured by Georg Neumann GmbH in 1928. It is, moreover, the fist “mass produced” condenser microphone. It employs a simple tube circuit amplifier matching the “high impedance” capacitor sound transducer to low Impedance microphone output. The tube is a Telefunken RE 084k, a large glass direct heated low noise triode. The triode drives a 6,5.1 output transformer achieving a 300 ohm (1 kHz) nominal output impedance. All the parts are housed inside the cylindrical body. The microphone was designed to fit interchangeable capsules. Several capsule heads were available with different polar patterns and capsule design, two locking ways were in use (screw and bayonet). The CMV 3 had torpedo head with threaded capsule. The CMV 3a had bayonet head capsule coupling. The first capsule (1927) was the CM 3, a PVC/G pressure (omnidirectional) capacitor capsule. Starting from 1932 both pressure / pressure gradient (omni / directional) PVC/G capsules were available for the CMV 3a. These were the M7, M8 and M9 having respectively cardiod, bidirectional and omnidirectional patterns. Later, in 1953, the M 48 and M 48a capsules were available to fit the CMV 3 and the U 47 P (a special torpedo head U 47 produced for Philips). These special threaded capsules feature a KK 53 aluminium pressure transducer. The CMV 3 microphones were large and heavy. They have a diameter of 9 mm with a length of approximately 40 cm for an overall weight of 3 kg ! The CMV 3 is known as ” The Neumann Bottle”. These microphones were employed extensively in the 1936 Olympic Games in Berlin. The CMV 3 is still a quality microphone today. The CMV 3 had both battery and AC power supplies. Telefunken, an AEG acquired market rights for the CMV 3 so most of them bear Telefunken logos and codes.