Electrovoice 664 - Vintage 1950s Cardioid 'Variable D' Microphone in excellent fully working condition.
The Electro-Voice Model 664 is a cardioid microphone of the dynamic type with only one moving element. It is designed specifically for public address applications. The cardioid pattern is obtained through use of three sound entrances located in the back of the diaphragm. These three sound entrances, each utilizing the proper acoustical impedance, combine to form one effective back entrance which varies in distance from the diaphragm inversely with frequency. The resulting phase and amplitude conditions produce a uniform cardioid pattern over a wide frequency range. This variable front-to-back distance along with dynamic-type construction affords high resistance to mechanical shock and eliminates proximity effect.
The Model 664 is an all-purpose public address microphone designed to fulfill requirements of wide-range reproduction under a great variety of conditions. Because of its excellent and uniform polar response, it is especially useful in locations where acoustic feedback, ambient noise, and severe reverberation exist. The preferred instrument for serious home and semi-professional recording, the 664 is also an ideal choice for quality sound reinforcement systems, particularly where acoustic problems exist. It is equipped with a pop-proof wire mesh grille which minimizes wind and breath blasts. The Model 664 may be used on a floor or desk stand or carried in the hand. This all-purpose microphone features the exclusive Electro-Voice Acoustalloy® diaphragm. The non-metallic diaphragm permits smooth response over a wide frequency range and withstands high humidity, temperature extremes, severe mechanical shocks, and the corrosive effects of salt air. It is practically indestructible with normal use.
Specifications
Generating element: Dynamic.
Frequency response: Uniform from 60 to 15,000 Hz.
Impedance: 150 ohm and high impedance.
Output Level: 150 ohm, -58 dB, EIA sensitivity rating, -149 dB.
High Impedance, -58 dB, EIA sensitivity rating, -151 dB.
Polar Pattern: Cardioid, uniform front-to-back discrimination. See Figure 2.
Diaphragm: Electro-Voice Acoustalloy.
Case: Pressure-cast zinc.
Finish: Satin Chrome (available in non-reflecting gray as Model 664A or in
decorative gold as Model 664G.
Dimensions: Diameter: 1⅞", maximum. Length: 73/16".
Net Weight: 1 lb., 12 oz., without cable.
Stand Coupler: ⅝"-27 thread on stud.