Contact microphone

Often used as acoustic leakage probes, they also enjoy wide usage by electroacoustic music artists experimenting with sound.

Contact microphones can be used to amplify sound from acoustic musical instruments,[2] to sense drum hits, for triggering electronic samples, and to record sound in challenging environments, such as underwater under high pressure.

[3] Contact microphones based on piezoelectric materials are passive and high-impedance, and they sound tinny without a matching preamp.

Instead of being used as a microphone, they alternatively may be used to produce sound (typical used as the buzzer in computer motherboards) by sending voltages to them.

Moving coil microphone contact microphones operate by suspending a coil of wire within a magnetic field or alternatively by suspending a magnet above a fixed coil, to induce a signal directly from the object's vibrations.