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The Electro-Voice Model 667A
Broadcast Dynamic Cardioid — April, 1965

Electro-Voice Model 667A

Description and Applications
The Electro-Voice Model 667A is a dynamic cardioid microphone designed for boom mounting in broadcasting and recording. Not simply an impro­visation on existing equipment, the 667A has been created specifically to overcome the problems encountered in boom applications. A specially designed shock mount provides effective isolation from mechanical noise, and the integral Acoustifoam windscreen virtually eliminates noise caused by motion of the microphone through the air. Unusually light in weight, the 667A is easily maneuverable. The shock isolation and windscreen systems are readily removable for service or replacement. Very low sensitivity to induced hum permits use close to lights, AC lines, etc.


An outstanding feature of the 667A is the self-contained computer-type programming board which permits a total of six different frequency response curves. The programming panel is part of a versatile passive equalizer which is completely self-contained; no external equipment or special connecting cables are required. The variations from flat response, thus made available, permit the 667A to overcome acoustical problems and background noise, make possible special effects, and enable its use mixed with existing microphones of differing responses.

Frequency response

The use of Continuously Variable-D, a highly developed version of the pat­ented Electro-Voice Variable-D principle, makes possible extremely uni­form rejection of unwanted background noise. The rejection pattern is un­usually symmetrical in all planes. The CV-D principle, as employed in the 667A, uses a matched pair of slotted tubes coupled to the back of the diaphragm. The acoustic length of the tubes varies inversely with sound frequency, permitting them to phase out unwanted sound from all portions of the audible spectrum for maximum front-to-back ratio. The mic’s single moving element is a diaphragm of Electro-Voice Acoustalloy which is im­pervious to effects of temperature, humidity, and shock. CV-D permits optimum diaphragm damping, impossible with less sophisticated designs, for minimum wind and mechanical noise pickup and proximity effect.

Polar response


  • Generating Element: Dynamic

  • Frequency Response: Uniform 40 to 10,000 Hz (See Figure 2)

  • Polar Pattern: Cardioid (See Figure 3)

  • Impedance: 50, 150, 250 ohms, selected at rear of case by moving one pin

  • Output Level: -51 dB on 250 or 150 ohm tap, -52 dB on 50 ohm tap

  • Hum Pickup Level: -121 dBm (Reference .001 gauss field)

  • Diaphragm: Electro-Voice Acoustalloy

  • Finish: Non-reflecting gray

  • Cable Connector: Switchcraft A3F

  • Net Weight: 1 lb., 8 oz. (.68kg) less cable

Wiring diagram Programming panel Mount, connections

Illustrations and text courtesy of Electro-Voice,
Engineering Data Sheet Part No. 535698-407

Electro-Voice Model 667A Electro-Voice Model 667A Electro-Voice Model 667A Electro-Voice Model 667A Electro-Voice Model 667A Electro-Voice Model 667A Electro-Voice Model 667A Electro-Voice Model 667A Electro-Voice Model 667A Electro-Voice letter Electro-Voice Model 667A Electro-Voice Model 667A Electro-Voice Model 667A E-V 668 magazine advertisement

A magazine advertisement for the E-V 668, as mentioned in the letter above.

Electro-Voice 667A data sheet

Download the specification sheet for this mic.

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