A contact microphone, also known as a piezo microphone, is a form of

microphone A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public ...

that senses audio vibrations through contact with solid objects. Unlike normal air microphones, contact microphones are almost completely insensitive to air

vibration Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic function, periodic, such as the motion of a pendulum ...

s but transduce only structure-borne sound. Often used as acoustic leakage probes, they also enjoy wide usage by noise music artists experimenting with sound. Contact microphones can be used to amplify sound from acoustic musical instruments, to sense drum hits, for triggering electronic samples, and to record sound in challenging environments, such as underwater under high pressure. Contact microphones based on piezo materials are passive and high-impedance, and they sound tinny without a matching

preamp A preamplifier, also known as a preamp, is an electronic amplifier that converts a weak electrical signal into an output signal strong enough to be noise-tolerant and strong enough for further processing, or for sending to a power amplifier ...

. The most commonly available contact microphone element is made of a thin piezoelectric ceramic round glued to a thin brass or alloy metal disc. This center disc is positively charged while the brass disc is negatively charged. The voltage can be measured across those parts and then amplified to produce sound.

References

{{Reflist Microphones

See also

References