Microphonics

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Microphonics

Microphonics describes the phenomenon where certain components in electronic

Electronics

Electronics refers to the flow of charge through nonmetal electrical conductor , whereas electrical refers to the flow of charge through metal electrical conductor....
devices transform mechanical vibration

Vibration

Vibration refers to mechanical oscillations about an equilibrium point. The oscillations may be periodic function such as the motion of a pendulum or random such as the movement of a tire on a gravel road....
s (ringing) into an undesired electrical signal (noise). The term is derived by analogy to older microphone

Microphone

A microphone, sometimes referred to as a mike or?more recently?mic, is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal....
s where that behavior is inherent in the design, while with modern electronics it is sometimes an intentionally added effect.

When electronic equipment was built using vacuum tube

Vacuum tube

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Encyclopedia

Microphonics describes the phenomenon where certain components in electronic

Electronics

Vibration

Microphone

Vacuum tube

In electronics, a vacuum tube, electron tube , thermionic valve, or just valve is a device used to amplifier, switch, otherwise modify, or create an Electricity signal by controlling the movement of electrons in a low-pressure space....
s, microphonics used to be a very serious design problem. The charged elements in the vacuum tubes would vibrate and the motion would change the distance between the elements, producing charge flows in and out of the tube in a manner identical to a capacitor microphone. A system sufficiently susceptible to microphonics could experience feedback

Audio feedback

Audio feedback is a special kind of feedback which occurs when a sound loop exists between an audio input and an audio output . In this example, a signal received by the microphone is Amplifier and passed out of the loudspeaker....
.

With the advent of solid state electronics (transistor

Transistor

In electronics, a transistor is a semiconductor device commonly used to Electronic amplifier or switch Electronics signals. A transistor is made of a solid piece of a semiconductor material, with at least three terminals for connection to an external circuit....
s), this major source of microphonics was eliminated but smaller sources still remain. The ceramic

Ceramic

File:Bridge from dental porcelain.jpgFile:Qing vase p1070256.jpgA ceramic is an inorganic, nonmetal solid prepared by the action of heat and subsequent cooling....
dielectric

Dielectric

A dielectric is a nonconducting substance, i.e. an Insulator . The term was coined by William Whewell in response to a request from Michael Faraday....
s used in high-K capacitor

Capacitor

A capacitor or condenser is a Passive component electronic component consisting of a pair of electrical conductor separated by a dielectric....
s ("Z5U" and "X7R") are piezoelectric

Piezoelectricity

Piezoelectricity is the ability of some materials to generate an electric potential in response to applied mechanical Stress . This may Piezoelectricity#Crystal classes of a separation of electric charge across the crystal lattice....
and will directly transform mechanical vibration into a voltage in exactly the same fashion as a ceramic microphone . Wiring and cables can also exhibit microphonics as charged conductors move around and various materials can develop triboelectric ("static") charges that couple to the electronic circuits.

The sound of guitar amplifiers that incorporate the electronic chassis

Chassis

A chassis consists of a Frame that supports an inanimate object, analogous to an animal's skeleton, for example in a motor vehicle or a firearm....
into the same cabinet as the speaker are susceptible to microphonics. Though a guitar amplifier's microphonics distortion is sometimes appreciated as part of the "special sound" of a guitar amplifier, a faulty vacuum tube

Vacuum tube

In electronics, a vacuum tube, electron tube , thermionic valve, or just valve is a device used to amplifier, switch, otherwise modify, or create an Electricity signal by controlling the movement of electrons in a low-pressure space....
or other component can cause out of control feedback. Unwanted microphonics-related audible distortions can often be alleviated by using commercially available vacuum tube dampers.

Other uses

The term is sometimes used to describe the sounds physically produced by mechanical vibrations or knocks on the wires of a headphone or in-ear monitor
In-ear monitor

In ear monitors are devices used by performers to hear a mix of microphones and/or instruments that are on the stage. They are often custom fitted to the individual's ears and provide a high level of noise reduction from stage noise....
, where no current induction occurs.