Electro-Voice Cardyne II

From the Electro-Voice data sheet:

The CARDYNE microphones are cardioid unidirectional dynamic types operating on the E-V Mechanophase principle. They utilize dual phase shifting diaphragms to produce a high degree of uni-directivity at all frequencies.

The CARDYNE models are designed for extremely accurate reproduction of music and speech. The directivity gives it unusual versatility in increasing the working distance from the user by reducing reverberation and acoustic feed-back. High output provides an excellent signal-to-noise ratio for broadcasting studio pick-up.

CARDYNE I I output level rating power 50 db below 6 milliwatts for 10 dynes/cm². Voltage (high impedance) 50 db below 1 volt/ dyne/cm², open circuit.

Voltage developed by normal speech (10 dynes/cm²): .0034 volt across Hi-Z output.

IMPEDANCE: Selector switch at rear of microphone for selection of high or low impedance.

FREQUENCY RESPONSE: CARDYNE II: 40 to 10,000 Hz. substantially flat.

POLAR PATTERN: 5. Cardioid. Wide angle front pickup with forward gain. Highly attenuated back pickup.

Vintage Mike's blog post about the EV Cardyne II microphone.