Condenser Mic Information: Learning What a Condenser Microphone is and How it Works

Condenser Mic Information: Learning What a Condenser Microphone is and How it Works
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The condenser mic was invented in the late 1910’s to deal with problems of signal to noise ratio and frequency response found in the previously popular carbon microphones. E.E. Wente at Bell Labs was the first to develop the 394 condenser microphone, shortly followed by the RCA 4AA. Since then the condenser microphone has been refined to include various pickup patterns, such as omnidirectional capabilities, switchable pickup patterns and more durable diaphragms to accommodate more diverse applications.

How it Works

Condenser Microphone Schematic

The use of the term condenser is actually not appropriate, as it uses a capacitor to convert an acoustic signal to electrical energy. This is why it is sometimes referred to as a capacitor microphone.

The condenser microphone is made up of two plates: a front plate and a back plate. The front plate is known as a diaphragm and is made of a very light material. As acoustic energy hits the diaphragm it vibrates, thus reducing and increasing the distance between the two plates.

When the plates are close, capacitance, or the change of current, increases and when the plates are farther apart, it decreases.

A power supply is necessary in order to retain constant voltage on the capicitor. This is supplied through a battery or phantom power of 48 voltage.

Applications and Uses

The condenser mic is known for its sensitive signal which allows it to capture small nuances in sound with low feedback. Coupled with a need for an external source of power, condenser microphones are most frequently used in a studio setting to record a diverse array of instruments and vocal performances. It is rare to see a condenser microphone used in a live setting because of their sensitivity. A shotgun microphone, used for film and broadcasting, is a type of condenser microphone that is both extremely directional and made of more durable material than other condenser microphones for use in unconventional settings.

Comparison to Other Microphones

The condenser mic is built to be sensitive to its sound source and is different from other microphones. A dynamic microphone, for instance, is known for its durability and performance even with loud sound signals. It also does not require phantom power to work which makes it the most popular choice for live performances. A dynamic microphone is not able to pick up the same nuance of sound as a condenser microphone, which is more likely to produce the warm sound needed for studio recordings.

Though they work differently, ribbon microphones perhaps come the closest to the sound of a condenser microphone, though they do differ. Condenser microphones are designed to accentuate certain frequencies, depending on their presumed use. Ribbon microphones, on the other hand, provide a much flatter frequency response and do not need phantom power to boost their signal.


Image Credit for Early Condenser Microphone: Wikimedia Commons/Gregory F. Maxwell

Image Credit for Condenser Microphone Schematic: Wikimedia Commons/Banco