Browse Definitions:
Definition

microphone

Contributor(s): Matthew Haughn

A microphone is a device that translates sound vibrations in the air into electronic signals or scribes them to a recording medium. Microphones enable many types of audio recording devices for purposes including communications of many kinds, as well as music and speech recording.

Frequently, microphones are designed for a given purpose. One of the main considerations, aside from the type of device, is what is being recorded. Directionality of microphones is one such consideration in microphone design. Omnidirectional  microphones are suited to recording all sounds in an area but poor for focusing on a single subject amongst background noise. Directional, bidirectional and shotgun microphones are suitable for interviews. However, the same effect is often achieved with two unidirectional devices, such as cardioid microphones.

The first electronic microphone was a liquid-based mechanism that used a diaphragm attached to a current-charged needle in a diluted sulfuric acid solution. This early microphone was not able to reproduce intelligible speech.

Since then, there have been and continue to be many types of microphone technologies, some of which are described below:

The first viable diaphragm microphones used a sheet of metal attached to a needle which scribed transmitted vibrations to a foil recording medium. When the needle moved over the foil after the scribing, the process was reversed and translated back to sounds again through the same metal diaphragm.

Carbon microphones were used in telephones for over one hundred years. These devices used the variable electrical resistance of carbon under pressure between metal plates to translate airborn sound waves into a electrical signal.

Condenser microphones use the varied electrical charge of a capacitor with a diaphragm acting as a one of the plates of a capacitor. The plate is biased by a fixed charge, often from a battery which also amplifies the signal. Capacitance varies with movement of the diaphragm in relation to the other plates providing the means to record the sound in electrical signal. Electret microphones used in cell phones and computers are a type of condenser microphone that use a polarized ferroelectric material.

Crystal microphones use a piezoelectric crystal that generates small amounts of electricity under compression of a diaphragm to provide the recording signal.

Dynamic microphones use a coil suspended in a magnetic field that may be attached to multiple membranes for extended frequency response. They use electro-magnetic induction to produce the signal. These microphones are well suited to stage performance.

Laser microphones use the vibrations of surfaces affected by sound waves to capture sound at distances. The lasers return at different angles due to the vibration and these changes are interpreted and translated into sound waves.

Due to similarities in function, microphones can operate as speakers. Generally, microphone-derived speakers are suited to high-frequency sounds like the STC company's microphone derived super-tweeter. Speakers can also operate as microphones, although they are generally suited for the capture of low frequencies.

Acmeschool provides an introduction to microphones:

This was last updated in December 2016

Continue Reading About microphone

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

SearchSecurity

  • black hat

    Black hat refers to a hacker who breaks into a computer system or network with malicious intent.

  • copyright

    Copyright is a legal term describing ownership of control of the rights to the use and distribution of certain works of creative ...

  • keylogger (keystroke logger or system monitor)

    A keylogger, sometimes called a keystroke logger or system monitor, is a type of surveillance technology used to monitor and ...

SearchHealthIT

  • population health management (PHM)

    Population health management (PHM) is a discipline within the healthcare industry that studies and facilitates care delivery ...

  • ICD-10-PCS

    The International Classification of Diseases, 10th Revision, Procedure Coding System (ICD-10-PCS) is a U.S. cataloging system for...

  • U.S. National Library of Medicine (NLM)

    The U.S. National Library of Medicine (NLM) is the largest biomedical library in the world.

SearchDisasterRecovery

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

  • mass notification system (MNS)

    A mass notification system is a platform that sends one-way messages to inform employees and the public of an emergency.

SearchStorage

  • open source storage

    Open source storage is data storage software developed in a public, collaborative manner that permits the free use, distribution ...

  • CompactFlash card (CF card)

    A CompactFlash card (CF card) is a memory card format developed by SanDisk in 1994 that uses flash memory technology to store ...

  • email archiving

    Email archiving (also spelled e-mail archiving) is a systematic approach to saving and protecting the data contained in email ...

SearchSolidStateStorage

  • RRAM or ReRAM (resistive RAM)

    RRAM or ReRAM (resistive random access memory) is a form of nonvolatile storage that operates by changing the resistance of a ...

  • JEDEC

    JEDEC is a global industry group that develops open standards for microelectronics.

  • M.2 SSD

    An M.2 SSD is a solid-state drive (SSD) that conforms to a computer industry specification written for internally mounted storage...

SearchCloudStorage

  • RESTful API

    A RESTful application program interface breaks down a transaction to create a series of small modules, each of which addresses an...

  • cloud storage infrastructure

    Cloud storage infrastructure is the hardware and software framework that supports the computing requirements of a private or ...

  • Zadara VPSA and ZIOS

    Zadara Storage provides block, file or object storage with varying levels of compute and capacity through its ZIOS and VPSA ...

Close