Microphones: Transducer Types

Microphones: The technical Basics

Microphones are used whenever the sound of a voice or an instrument needs to be reinforced – either on stage, in a rehearsal room, at presentations or recording at home or in a studio. There are three main technical characteristics that distinguish microphones from each other. These characteristics are important to understand to make the best choice for your needs:

Transducer type: How does the microphone physically pick up the sound and convert it into an electrical signal?
Polar pattern / directionality: From which direction does a microphone pick up the sound?
Frequency response: Is the output level or sensitivity of all frequencies the same?

Microphones: Transducer Types (Dynamic, Condenser, Ribbon)

The transducer is the heart of the microphone. It converts sound into an electricalsignal. The two most common transducer types are Dynamic and Condenser. Another more special type is the ribbon microphone.

Dynamic Microphones

Dynamic microphones employ a diaphragm, a voice coil and a magnet. The voice coil is surrounded by a magnetic field and is attached to the rear of the diaphragm. The motion of the voice coil in this magnetic field generates the electrical signal corresponding to the picked up sound.
Dynamic microphones have a relatively simple construction and are therefore economical and rugged. They can handle extremely high sound pressure levels and are largely unaffected by extreme temperatures or humidity.

Condenser Microphones

Condenser microphones are based on an electrically-charged diaphragm/ backplate assembly which forms a soundsensitive capacitor. When the diaphragm is set in motion through sound, the space between the diaphragm and the backplate is changing, and therefore the capacity of the capacitor. This variation in spacing produces the electrical signal. All condenser microphones need to be powered: either by batteries in the microphone or by phantom power (cf. Glossary p. 61) provided by a mixer. Condensers are more sensitive and can provide a smoother, more natural sound, particularly at higher frequencies.

Ribbon Microphones

A ribbon microphone is a type of dynamic microphone that uses a thin electrically conducting ribbon placed between the poles of a magnet. Ribbon microphones are typically bidirectional. They pick up sounds from in front of the microphone and from the rear but not the side (90 degree angle).