The Neumann Model U 87 Ai multi-directional condenser microphone
Scroll down part of the way to see the U 87.
Hear a voice recording made with this mic.
Hear an acoustic guitar recorded with this mic.
Description The U 87 is probably the best known and most widely used Neumann studio microphone. It is equipped with a large dual-diaphragm capsule with three directional patterns: omni-directional, cardioid and figure 8. These are selectable with a switch below the head grille. A 10 dB attenuation switch is located on the rear. It enables the microphone to handle sound pressure levels up to 127 dB without distortion. Furthermore, the low-frequency response can be reduced to compensate for proximity effect.
Applications The U 87 Ai condenser microphone is a large diaphragm microphone with three polar patterns and a unique frequency and transient response characteristic. Users recognize the microphone immediately by its distinctive design. It is a good choice for most general purpose applications in studios, for broadcasting, film and television. The U 87 Ai is used as a main microphone for orchestra recordings, as a spot mic for single instruments, and extensively as a vocal microphone for all types of music and speech.
Acoustic Features The U 87 is addressed from the front, marked with the Neumann logo. The frequency response of the cardioid and figure 8 directional characteristics are flat for frontal sound incidence, even in the upper frequency range. The microphone can be used very close to a sound source without the sound becoming unnaturally harsh. By means of a high-pass filter, interferences through subsonic and low frequencies are reduced remarkably.
Electrical Features The letter A in the name indicates a more recent generation, as compared to the U 87 i mics that were built from 1967 to 1986. Modifications apply to the electronic components of the microphone only; the capsule remains unchanged. The present-day circuitry increases the operational headroom of the U 87 Ai by supplying the bias voltages for the capsule through a reduced resistance. The result is a higher sensitivity of 10 dB for identical sound pressure levels, and an improved signal-to-noise ratio of 3 dB.
The Neumann Model U 87 multi-directional condenser microphone
From an eBay seller’s description: “This is the original Neumann U87, serial number 21773. This was the first version of the U87 which can operate on phantom power or from internal batteries. When operating on batteries, it can even feed an unbalanced mic input, such as on a cassette or portable digital recorder. Several people have asked about the XLR connector. The U87 has a standard three-pin XLR connector. The forth pin is the switch that turns on the batteries whenever an XLR connector is inserted. If there are no batteries installed, it runs on phantom power like any other condenser microphone.”
The fourth “pin” is the battery on-off switch.
Neumann produced two transistorized versions of the U 67: from 1967 to 1986, the phantom-powered U 87, and from 1968 to 1974, the AB-powered U 77. The capsule had to be slightly modified for the U 87, since with an electrically integrated central electrode, it would have been impossible to produce a figure-of-eight pattern without a DC-DC converter, so the two electrodes had to be isolated from one another and switched in phase on one side and out of phase on the other to create the figure-of-eight pattern. The U 87 A, on the other hand, which had its own DC-DC converter, uses the K67 capsule, now named K870/67.
Both models were equipped with a battery compartment, which, in the case of the U 77, accepted one 9-volt battery, and in the case of the U 87, two 22.5-volt batteries of the type at the time used by photographic flash guns. “By 1986, however,” as Stephan Peus relates, “these batteries were no longer obtainable and the battery compartment became otiose, so we decided to use it to accommodate a DC-DC converter of the kind used by the U 77 and therefore capable of delivering exactly 60 volts to the capsule. Now the signal-to-noise ratio of the (phantom-powered) U 87 A was exactly as good as that of the U 77 and all of 3 dB better than that of the U 87 without the ‘A’!”
In 1980, a slightly smaller version of the U 87 was launched: the U 89, which was handier and lighter. The U 89 used a smaller capsule, the K89, with a polyester diaphragm, and offered five different polar patterns: omnidirectional, wide cardioid, cardioid, hypercardioid and figure-of-eight. Its SPL handling was also 14 dB better than that of the U 87.
From Neumann, the Microphone Company, p. 83
The U 87 battery compartment (left) and battery monitor (right).
A tour of Berlin plus the history of the Neumann Company The city of Berlin, which has been home to Neumann for over 75 years, has been subjected to tremendous upheaval since the fall of the Berlin Wall.