Background noise or ambient noise is any

sound In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the br ...

other than the sound being monitored (primary sound). Background

noise Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrat ...

is a form of

noise pollution Noise pollution, or sound pollution, is the propagation of noise or sound with potential harmful effects on humans and animals. The source of outdoor noise worldwide is mainly caused by machines, transport and propagation systems.Senate Publi ...

interference Interference is the act of interfering, invading, or poaching. Interference may also refer to: Communications * Interference (communication), anything which alters, modifies, or disrupts a message * Adjacent-channel interference, caused by extra ...

. Background noise is an important concept in setting noise levels. Background noises include

environmental noise Environmental noise is an accumulation of noise pollution that occurs outside. This noise can be caused by transport, industrial, and Sport, recreational activities. Noise is frequently described as 'unwanted sound'. Within this context, envir ...

s such as

water waves In fluid dynamics, a wind wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result of the wind blowing over the water's surface. The contact distance in the direction of the wind is k ...

, traffic noise,

alarm ALARM (Air Launched Anti-Radiation Missile) is a British anti-radiation missile designed primarily to destroy enemy radars for the purpose of Suppression of Enemy Air Defenses (SEAD). It was used by the Royal Air Force, RAF and is still used by ...

s, extraneous

speech Speech is the use of the human voice as a medium for language. Spoken language combines vowel and consonant sounds to form units of meaning like words, which belong to a language's lexicon. There are many different intentional speech acts, suc ...

, bioacoustic noise from animals, and electrical noise from devices such as

refrigerator A refrigerator, commonly shortened to fridge, is a commercial and home appliance consisting of a thermal insulation, thermally insulated compartment and a heat pump (mechanical, electronic or chemical) that transfers heat from its inside to ...

air conditioning Air conditioning, often abbreviated as A/C (US) or air con (UK), is the process of removing heat from an enclosed space to achieve a more comfortable interior temperature, and in some cases, also controlling the humidity of internal air. Air c ...

, power supplies, and motors. The prevention or reduction of background noise is important in the field of

active noise control Active noise control (ANC), also known as noise cancellation (NC), or active noise reduction (ANR), is a method for reducing unwanted sound by the addition of a second sound specifically designed to cancel the first. The concept was first deve ...

. It is an important consideration with the use of

ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...

(e.g. for

medical diagnosis Medical diagnosis (abbreviated Dx, Dx, or Ds) is the process of determining which disease or condition explains a person's symptoms and signs. It is most often referred to as a diagnosis with the medical context being implicit. The information ...

or imaging),

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects o ...

, and sound reproduction.

Other uses

astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

, background noise or cosmic background radiation is

electromagnetic radiation In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...

from the sky with no discernible source. In

information architecture Information architecture (IA) is the structural design of shared information environments; the art and science of organizing and labelling websites, intranets, online communities and software to support usability and findability; and an emerging ...

, irrelevant, duplicate or incorrect information may be called background noise. In

physics Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...

and

telecommunication Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...

, background signal noise can be detrimental or in some cases beneficial. The study of avoiding, reducing or using signal noise is

information theory Information theory is the mathematical study of the quantification (science), quantification, Data storage, storage, and telecommunications, communication of information. The field was established and formalized by Claude Shannon in the 1940s, ...

. In

telephony Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunications services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is ...

, artificial comfort noise is used as a substitute for natural background noise, to fill in artificial silence created by discontinuous transmission systems using voice activity detection. Background noise can also affect concentration.

External links

How low noise levels are achieved in concert hallsBackground noise in acoustics (demo)
Acoustics Noise pollution Sound {{Acoustics-stub

Other uses

See also

External links