Neumann U87Ai Large Diaphragm Microphone

Over 50,000 U87 users can't be wrong, this microphone is the professional standard and sets the mark by which all others are measured. The U 87 will celebrate its 40th birthday in 2007 and is still going strong.

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 3 directional patterns: omnidirectional, cardioid, and figure-8. These are selectable with a switch below the headgrille. A 10 dB attenuation switch, located on the rear, 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.

Features:
Variable large diaphragm microphone

Pressure-gradient transducer with double membrane capsule

The studio microphone classic

3 directional characteristics: omni, cardioid, figure-8

Switchable low frequency roll-off

Switchable 10 dB pre-attenuation

Ideal as main and as support microphone in the most differing recording situations

Applications
The U 87 Ai condenser microphone is a large diaphragm microphone with 3 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
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.

Polar Patterns
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.

Electrical
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.

Filter and Attenuation
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 you to change the microphone's 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.

Technical Info

Acoustical Operating Principle: Pressure gradient transducer

Directional Pattern: Omnidirectional, cardioid, figure-8 plus

Frequency range: 20 Hz-20 kHz

Sensitivity at 1 kHz into 1 kohm: 20/28/22 mV/Pa*

Rated impedance: 200 ohms

Rated load impedance: 1000 ohms

Equivalent SPL CCIR 468-3: 26/23/25 dB*

Equivalent SPL DIN/IEC 651: 15/12/14 dB-A*

S/N ratio CCIR 468-3: 68/71/69 dB*

S/N ratio DIN/IEC 651: 79/82/80 dB*

Maximum SPL for THD 0.5%: 117 dB (cardioid)

Maximum SPL for THD 0.5% with preattenuation: 127 dB

Maximum output voltage: 390 mV

Dynamic range of the microphone amplifier cardioid DIN/IEC 651: 105 dB

Supply voltage: 48 V ? 4 V

Current consumption: 0.8 mA

Matching connectors: XLR3F

Weight: 500 g

Diameter: 56 mm

Length: 200 mm

* Omnidirectional/cardioid/figure-8

Renowned for its detailed sound, the dual large-diaphragm U 87 Ai is a studio standard on sources from drums to guitar amps to vocals. Its smooth frequency response has a rise beginning around 5kHz for clarity. Cardioid, omni, and figure-8 patterns. Handles 127 dB SPL with -10dB pad. Bass roll-off switch. Includes case, shockmount, windscreen, and cable.