Common name: Neumann M 249b
Production Status: Discontinued / Vintage
The Neumann M 249b is a special version of the M 49b microphone with a RF shielded 7-pin Tuchel connector manufactured from 1961 until 1964 when it was replaced by the M 249c. Although connectors are different there is no difference in powering. The M 49 is an high grade condenser microphone developed by Georg Neumann GmbH in partnership with the NWDR – Nordwestdeutscher Rundfunk (Northwest German Broadcasting) with the headquarters located in Hamburg. The M49 b in the first revision of the original M 49. The NWDR engineers worked al lot with CMV 3 and U 47 models so they discovered the limits of these microphones in live broadcasts. The main limit being that it was necessary to approach the microphone in order to change the polar pattern. The other limit was that the microphone sensitivity changes with the polar pattern. Moreover they noticed that most of the dramas would have had benefits from different microphone patterns depending on the atmosphere and settings being described. The M 49 was developed to overcome these problems. It was the first remotely controlled pattern microphone, continuously variable between omnidirectional through cardioid to bidirectional while maintaining a practically constant sensitivity. The pattern can be changed by slowing rotating a control potentiometer without any switching noise. The microphone amplifier was designed in cooperation with NWDR’s engineering department just to achieve this. Georg Neumann designed the microphone with some further improvements that later became the standard for Neumann’s products. The dual diaphragm capsule was housed in a new shaped head grille for the purpose of avoiding diffraction and interference typical of previous cylindrical head grilles (refer to Stephen Paul’s piece about the effect of U 47’s head grille). The U 47 has only limited damping for the tube and the capsule holder. The M 49 amplifier is mounted on a rubber disk decoupling the amp itself from the microphone housing. The M 49 development started in 1949 and the microphone was presented to German broadcasters in 1952. The microphone received several revisions and it was in production until 1974. The “b” version released in late 1959 is quite different from the previous one. The first version is easily recognizable by the absence of the Neumann logo, replaced by a “red gem”, while the M 49b and M 49c have the classic Neumann logo, and can only be distinguished by the microphone plate with the serial number. Several parts, including the microphone amplifier design are different from the previous version. The large dual diaphragm capsule is the K 49 made with MCF gold plated diaphragms, instead of the original PVC M7. The output transformer is now the Bv.11 having two secondary windings for 50/200 ohm nominal output impedance, wound with an electrostatic shield. The amplifier vacuum tube is the Telefunken AC 701 k. As the microphone was designed for broadcast applications its pre-amplifier circuit features built-in low and high frequencies attenuation. These microphones can be modified to achieve a full frequency response with lower phase distortion. The classic yoke mount holder isn’t a genuine Neumann accessory and it never was in the brand catalogue. It was manufactured by Danner – Berlin.