Neumann U 87 Ai studio set

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.

The U 87 Ai is addressed from the front, marked with the Neumann
logo. The frequency response of the cardioid and figure-8 directional
characteristics are very 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.

The dual-diaphragm capsule is elastically mounted and protected by a
large headgrille. A switch below the headgrille selects the three
directional patterns: omnidirectional, cardioid and figure-8. A window
above this switch shows the symbol of the selected characteristic.

The letter A in the name indicates a more recent generation, as
compared to the U 87 i microphones that were built from 1967 to 1986.
Modifications apply to the electronic components of the microphone only;
the capsule remained 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 S/N ratio of 3 dB.

A switch located at the rear attenuates the sensitivity by 10 dB.
When this switch is activated, the microphone accepts sound pressure
levels up to 127 dB (equivalent to a sound pressure of 45 Pa) without
distortion.

An additional switch at the rear allows to change
the microphones cutoff frequency. This reduces low frequency
interference directly at the input of the microphone amplifier.

This
setting also compensates for the unavoidable bass boost that occurs
with all pressure gradient transducers when they are used at close
distance (proximity effect).

The cardioid characteristic
maintains a smooth frequency response at a distance of 30 to 40 cm, the
figure-8 characteristic even at a distance of 15 to 20 cm.

*The design of the microphone is a registered design of the Georg Neumann GmbH in certain countries.