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This section offers you a comprehensive introduction to the Neumann company, as well as an extensive overview of the company history and the products which have previously been placed on the market.

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Neumann: A Name Stands for Quality and Precision
Despite all the progress in machines and production technology, manufacturing a high-quality microphone involved a great deal of handicraft, upon which the quality of these transducers and a reputation such as Neumann's ultimately depend.

Capsule Building - A Science in Itself
The performance of the condenser microphone, now manufactured in an extremely wide range of models, remains largely reliant on the precision engineering involved in capsule production.

The common centre electrode found on a double diaphragm capsule contains a large number of critical drill holes, some of which are blind. The depth of these blind holes determines the volume of air trapped behind the diaphragm. This volume, which inhibits the movements of the diaphragm, determines the transducing capability of the condenser microphone.

The dimensions of the holes, and their accurate machining becomes even more crucial when the electrode is produced in two halves. With this design the two halves of the capsule can be electrically connected, and similarly separated, by means of an isolating intermediate layer, thereby making it possible to switch the directional characteristic with the available polarisation voltage.

To smooth the surface of the electrodes two different processes are employed. For microphone capsules whose surface lie on one plane a lapping process can achieve a surface flatness of 0.3 µm and a plane parallelism of +/ 1 µm between the front and the back of the electrode. In some cases a capsule's surface may be in two planes. This may be because the distance between the diaphragm and the electrode has already been determined by the second plane of the electrode. In such cases the finishing is performed on special lathes.

After lapping or lathe finishing, the holes must be deburred, followed by a visual inspection using a powerful microscope.

Diaphragms are made from a 6.3 µm thick polyester foil, such as Mylar. This is first attached to brass rings, then put into a container which holds it while gold is applied under vacuum to a uniform layer 300 Angstroms thick (0.03 µm). The external diameter of the capsule is approximately 34 mm. The diaphragm is fitted approximately 40 µm in front of the electrode and is 6.3 µm thick. When a sound pressure of 1 Pa is applied the diaphragm movement is no more than 10 nm. By comparison, the wavelength of violet light is 400 nm.

The mechanical advantages being achieved under these microscopic proportions is best put into perspective by illustrating thus: if a microphone capsule were to be given a scale on which the amplitude for 1 Pa were represented by 1 mm the capsule under manufacture would have to have a diaphragm spacing of 4 m, and the diameter of the capsule would be more than 3 km.

One type of capsule, the KK 88 from the KM 88 microphone, uses pure nickel as the diaphragm material 0.0007 mm thick (0.7 µm).

On assembly of the capsule aluminum foil spacer rings, 40 µm thick are attached to the middle and the edge of the electrode. The lead in contact for the polarisation voltage is fitted in the centre. This is an assembly device that enables the capsule to be directly connected to a test instrument, with which the capacitance is measured and the mechanical strength of the diaphragm tested. This is done by measuring the change in the basic capacitance after the polarisation voltage has been applied.

Microphone-lab (in the 50's)
Microphone-lab (in the 50's)
Microphone-lab (in the 50's)
Microphone-lab (in the 50's)
Microphone-lab (in the 50's)
Microphone-lab (in the 50's)
Measuring equipment (in the 50's)
Measuring equipment (in the 50's)
Quality Must Be Measurable
To meet the operating conditions encountered in the studio the microphones are subject to testing throughout their manufacture. The capsules alone undergo more than 50 different tests before final assembly.

Since the very beginning in 1928 Neumann condenser microphones have always operated on an audio frequency circuit, with the capsule consequently acting as a very high impedance generator, rendering it highly sensitive to moisture. And as moisture represents one of the most common operational hazards of a warm recording studio, Neumann has paid great attention to all aspects of insulation.

Quality control devoted to this aspect includes a moisture chamber, in which capsules are placed until both the diaphragm and microphone body are dripping wet. Even under these conditions insulation resistances to the order of 20 x 106 Mohms are measured in the capsules.

Another test is to cool the microphones to slightly above freezing point and then place them in a chamber with 100% humidity, at a relatively high temperature. The spontaneous moisture formation that follows infiltrates not only the capsule but the entire electronic circuitry. It would have to be an extremely uncomfortable studio to recreate such conditions to say the least, but just in case, we would like to point out that every type of Neumann condenser microphone will pass this test.

Mounting the diaphragms onto capsule body (1996)
Mounting the diaphragms onto capsule body (1996)
Assembling the capsule heads (1996)
Assembling the capsule heads (1996)
Equipment for static measurements (1996)
Equipment for static measurements (1996)
Anechoic chamber (1996)
Anechoic chamber (1996)


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