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Noise is unwanted
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 ...
considered unpleasant, loud or disruptive to
hearing
Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is audit ...
. From a physics standpoint, there is no distinction between noise and desired sound, as both are
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, such as the motion of a pendulum—or random, su ...
s through a medium, such as air or water. The difference arises when the brain receives and perceives a sound.
Acoustic noise is any sound in the acoustic domain, either deliberate (e.g., music or speech) or unintended. In contrast,
noise in electronics may not be audible to the human ear and may require instruments for detection.
In
audio engineering
Audio most commonly refers to sound, as it is transmitted in signal form. It may also refer to:
Sound
* Audio signal, an electrical representation of sound
*Audio frequency, a frequency in the audio spectrum
* Digital audio, representation of sou ...
, noise can refer to the unwanted residual electronic noise signal that gives rise to acoustic noise heard as a
hiss. This signal noise is commonly measured using
A-weighting or
ITU-R 468 weighting.
In
experimental science
An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when ...
s, noise can refer to any random fluctuations of data that hinders perception of a signal.
Measurement
Sound is measured based on the
amplitude
The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplit ...
and
frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
of a sound wave. Amplitude measures how forceful the wave is. The energy in a sound wave is measured in
decibels (dB), the measure of
loudness
In acoustics, loudness is the subjective perception of sound pressure. More formally, it is defined as, "That attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud". The relation of ph ...
, or
intensity of a sound; this measurement describes the amplitude of a sound wave. Decibels are expressed in a
logarithmic scale
A logarithmic scale (or log scale) is a way of displaying numerical data over a very wide range of values in a compact way—typically the largest numbers in the data are hundreds or even thousands of times larger than the smallest numbers. Such a ...
. On the other hand, pitch describes the frequency of a sound and is measured in
hertz (Hz).
The main instrument to measure sounds in the air is the
Sound Level Meter. There are many different varieties of instruments that are used to measure noise -
Noise Dosimeters are often used in occupational environments, noise monitors are used to measure environmental noise and
noise pollution
Noise pollution, also known as environmental noise or sound pollution, is the propagation of noise with ranging impacts on the activity of human or animal life, most of them are harmful to a degree. The source of outdoor noise worldwide is ma ...
, and recently
smartphone
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
-based sound level meter applications (apps) are being used to crowdsource and map recreational and community noise.
A-weighting is applied to a sound spectrum to represent the sound that humans are capable of hearing at each frequency. Sound pressure is thus expressed in terms of dBA. 0 dBA is the softest level that a person can hear. Normal speaking voices are around 65 dBA. A rock concert can be about 120 dBA.
Recording and reproduction
In audio,
recording
A record, recording or records may refer to:
An item or collection of data Computing
* Record (computer science), a data structure
** Record, or row (database), a set of fields in a database related to one entity
** Boot sector or boot record, r ...
, and
broadcast
Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum ( radio waves), in a one-to-many model. Broadcasting began ...
systems, audio noise refers to the residual low-level sound (four major types: hiss, rumble, crackle, and hum) that is heard in quiet periods of program. This variation from the expected pure sound or silence can be caused by the audio recording equipment, the instrument, or ambient noise in the recording room.
In
audio engineering
Audio most commonly refers to sound, as it is transmitted in signal form. It may also refer to:
Sound
* Audio signal, an electrical representation of sound
*Audio frequency, a frequency in the audio spectrum
* Digital audio, representation of sou ...
it can refer either to the acoustic noise from loudspeakers or to the unwanted residual electronic noise signal that gives rise to acoustic noise heard as hiss. This signal noise is commonly measured using A-weighting or
ITU-R 468 weighting
Noise is often generated deliberately and used as a
test signal
Test(s), testing, or TEST may refer to:
* Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities
Arts and entertainment
* ''Test'' (2013 film), an American film
* ''Test'' (2014 film), ...
for audio recording and reproduction equipment.
Environmental noise
Environmental noise is the accumulation of all noise present in a specified environment. The principal sources of environmental noise are surface motor vehicles, aircraft, trains and industrial sources. These noise sources expose millions of people to noise pollution that creates not only annoyance, but also significant health consequences such as elevated incidence of hearing loss, cardiovascular disease, and many others. Urban noise is generally not of an intensity that causes hearing loss but it interrupts sleep, disturbs communication and interferes with other human activities. There are a variety of mitigation strategies and controls available to reduce sound levels including source intensity reduction,
land-use planning strategies,
noise barriers and
sound baffle
A sound baffle is a construction or device which reduces the strength (level) of airborne sound. Sound baffles are a fundamental tool of noise mitigation, the practice of minimizing noise pollution or reverberation. An important type of sound ...
s, time of day use regimens, vehicle operational controls and
architectural acoustics
Architectural acoustics (also known as building acoustics) is the science and engineering of achieving a good sound within a building and is a branch of acoustical engineering. The first application of modern scientific methods to architectura ...
design measures.
Regulation
Certain geographic areas or specific occupations may be at a higher risk of being exposed to constantly high levels of noise; regulation may prevent negative health outcomes. Noise regulation includes statutes or guidelines relating to sound transmission established by national, state or provincial and municipal levels of government. Environmental noise is governed by laws and standards which set maximum recommended levels of noise for specific land uses, such as residential areas, areas of outstanding natural beauty, or schools. These standards usually specify measurement using a
weighting filter
A weighting filter is used to emphasize or suppress some aspects of a phenomenon compared to others, for measurement or other purposes.
Audio applications
In each field of audio measurement, special units are used to indicate a weighted measure ...
, most often A-weighting.
United States
In 1972, the
Noise Control Act The Noise Pollution and Abatement Act of 1972 is a statute of the United States initiating a federal program of regulating noise pollution with the intent of protecting human health and minimizing annoyance of noise to the general public.
The Act e ...
was passed to promote a healthy living environment for all Americans, where noise does not pose a threat to human health. This policy's main objectives were: (1) establish coordination of research in the area of
noise control
Noise control or noise mitigation is a set of strategies to reduce noise pollution or to reduce the impact of that noise, whether outdoors or indoors.
Overview
The main areas of noise mitigation or abatement are: transportation noise control, ...
, (2) establish federal standards on noise emission for commercial products, and (3) promote public awareness about noise emission and reduction.
The
Quiet Communities Act of 1978
Quiet may refer to:
* Silence, a relative or total lack of sound
In music
* The Quiett (born 1985), South Korean rapper
* Quiet (album), ''Quiet'' (album), a 1996 John Scofield album
* "Quiet", a song by Lights, from her album ''The Listening (Li ...
promotes noise control programs at the state and local level and developed a research program on noise control. Both laws authorized the
Environmental Protection Agency to study the effects of noise and evaluate regulations regarding noise control.
The
National Institute for Occupational Safety and Health
The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the C ...
(NIOSH) provides recommendation on noise exposure in the workplace. In 1972 (revised in 1998), NIOSH published a document outlining recommended standards relating to the occupational exposure to noise, with the purpose of reducing the risk of developing permanent hearing loss related to exposure at work. This publication set the recommended exposure limit (REL) of noise in an occupation setting to 85 dBA for 8 hours using a 3-dB exchange rate (every 3-dB increase in level, duration of exposure should be cut in half, i.e., 88 dBA for 4 hours, 91 dBA for 2 hours, 94 dBA for 1 hour, etc.). However, in 1973 the
Occupational Safety and Health Administration
The Occupational Safety and Health Administration'' (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agenc ...
(OSHA) maintained the requirement of an 8-hour average of 90 dBA. The following year, OSHA required employers to provide a
hearing conservation program
Hearing conservation programs are designed to prevent hearing loss due to noise. Hearing conservation programs require knowledge about risk factors such as noise and ototoxicity, hearing, hearing loss, protective measures to prevent hearing loss ...
to workers exposed to 85 dBA average 8-hour workdays.
Europe
The
European Environment Agency regulates noise control and surveillance within the
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
. The
Environmental Noise Directive was set to determine levels of noise exposure, increase public access to information regarding environmental noise, and reduce environmental noise. Additionally, in the European Union, underwater noise is a pollutant according to the
Marine Strategy Framework Directive The Marine Strategy Framework Directive (MSFD; full title: ''Directive 2008/56/EC of the European Parliament and of the Council of 17 June 2008 establishing a framework for community action in the field of marine environmental policy'') is a Europea ...
(MSFD).
The MSFD requires EU
Member States to achieve or maintain
Good Environmental Status Good Environmental Status is a qualitative description of the state of the seas that the European Union's Marine Strategy Framework Directive requires its Member States to achieve or maintain by the year 2020.
Good Environmental Status is described ...
, meaning that the "introduction of energy, including underwater noise, is at levels that do not adversely affect the marine environment".
Health effects
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Exposure to noise is associated with several negative health outcomes. Depending on duration and level of exposure, noise may cause or increase the likelihood of
hearing loss
Hearing loss is a partial or total inability to Hearing, hear. Hearing loss may be present at birth or acquired at any time afterwards. Hearing loss may occur in one or both ears. In children, hearing problems can affect the ability to Language ...
,
high blood pressure,
ischemic heart disease,
sleep disturbances
A sleep disorder, or somnipathy, is a medical disorder of an individual's sleep patterns. Some sleep disorders are severe enough to interfere with normal physical, mental, social and emotional functioning. Polysomnography and actigraphy are tests ...
,
injuries
An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, or o ...
, and even decreased school performance.
When noise is prolonged, the body's stress responses can be triggered; which can include increased heartbeat, and rapid breathing. There are also causal relationships between noise and psychological effects such as annoyance, psychiatric disorders, and effects on psychosocial well-being.
Noise exposure has increasingly been identified as a
public health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...
issue, especially in an occupational setting, as demonstrated with the creation of NIOSH's Noise and Hearing Loss Prevention program. Noise has also proven to be an
occupational hazard
An occupational hazard is a hazard experienced in the workplace. This encompasses many types of hazards, including chemical hazards, biological hazards (biohazards), psychosocial hazards, and physical hazards. In the United States, the Nation ...
, as it is the most common work-related pollutant. Noise-induced hearing loss, when associated with noise exposure at the workplace is also called
occupational hearing loss
Occupational hearing loss (OHL) is hearing loss that occurs as a result of occupational hazards, such as excessive noise and ototoxic chemicals. Noise is a common workplace hazard, and recognized as the risk factor for noise-induced hearing loss ...
. For example, some occupational studies have shown a relation between those who are regularly exposed to noise above 85 decibels to have higher blood pressure than those who are not exposed.
Hearing loss prevention
While
noise-induced hearing loss
Noise-induced hearing loss (NIHL) is a hearing impairment resulting from exposure to loud sound. People may have a loss of perception of a narrow range of frequencies or impaired perception of sound including sensitivity to sound or ringing i ...
is permanent, it is also preventable. Particularly in the workplace, regulations may exist limiting
permissible exposure limit
The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits are established by the Occupational ...
to noise. This can be especially important for professionals working in settings with consistent exposure to loud sounds, such as
musician
A musician is a person who composes, conducts, or performs music. According to the United States Employment Service, "musician" is a general term used to designate one who follows music as a profession. Musicians include songwriters who wri ...
s, music teachers and
audio engineer
An audio engineer (also known as a sound engineer or recording engineer) helps to produce a recording or a live performance, balancing and adjusting sound sources using equalization, dynamics processing and audio effects, mixing, reproduction, ...
s. Examples of measures taken to prevent noise-induced hearing loss in the workplace include engineering noise control, the
Buy-Quiet initiative, creation of the
Safe-In-Sound award
The Safe-in-Sound Excellence in Hearing Loss Prevention Award is an occupational health and safety award that was established in 2007 through a partnership between the National Institute for Occupational Safety and Health (NIOSH) and the National ...
, and noise surveillance.
Literary views
Roland Barthes
Roland Gérard Barthes (; ; 12 November 1915 – 26 March 1980) was a French literary theorist, essayist, philosopher, critic, and semiotician. His work engaged in the analysis of a variety of sign systems, mainly derived from Western popula ...
distinguishes between
physiological noise, which is merely
heard, and
psychological noise, which is actively
listened to. Physiological noise is felt subconsciously as the vibrations of the noise (sound) waves physically interact with the body while psychological noise is perceived as our conscious awareness shifts its attention to that noise.
Luigi Russolo
Luigi Carlo Filippo Russolo (30 April 1885 – 4 February 1947) was an Italian Futurist painter, composer, builder of experimental musical instruments, and the author of the manifesto ''The Art of Noises'' (1913). He is often regarded as one of ...
, one of the first composers of
noise music,
wrote the essay ''
The Art of Noises
''The Art of Noises'' ( it, L'arte dei Rumori) is a Futurist manifesto written by Luigi Russolo in a 1913 letter to friend and Futurist composer Francesco Balilla Pratella. In it, Russolo argues that the human ear has become accustomed to the ...
.'' He argued that any kind of noise could be used as music, as audiences become more familiar with noises caused by technological advancements; noise has become so prominent that pure sound no longer exists.
Avant-garde
The avant-garde (; In 'advance guard' or ' vanguard', literally 'fore-guard') is a person or work that is experimental, radical, or unorthodox with respect to art, culture, or society.John Picchione, The New Avant-garde in Italy: Theoretical ...
composer
Henry Cowell claimed that technological advancements have reduced unwanted noises from machines, but have not managed so far to eliminate them.
Felix Urban sees noise as a result of cultural circumstances. In his comparative study on sound and noise in cities, he points out that noise regulations are only one indicator of what is considered as harmful. It is the way in which people live and behave (acoustically) that determines the way how sounds are perceived.
See also
*
Association of Noise Consultants The Association of Noise Consultants (ANC) is a UK-based organisation of companies that are engaged in the business of acoustics, noise and vibration consulting. It was established in 1973.
Overview
There is a great range of specialisations within ...
*
Background noise
Background noise or ambient noise is any sound other than the sound being monitored (primary sound). Background noise is a form of noise pollution or interference. Background noise is an important concept in setting noise levels.
Background n ...
*
Colors of noise
In audio engineering, electronics, physics, and many other fields, the color of noise or noise spectrum refers to the power spectrum of a noise signal (a signal produced by a stochastic process). Different colors of noise have significantly ...
*
Impulse noise (acoustics)
Impulse noise is a category of ( acoustic) noise that includes unwanted, almost instantaneous (thus impulse-like) sharp sounds (like clicks and pops)—typically caused by electromagnetic interference, scratches on disks, gunfire, explosions, and ...
*
International Noise Awareness Day
*
Intonarumori
Intonarumori are experimental musical instruments invented and built by the Italian futurist Luigi Russolo between roughly 1910 and 1930. There were 27 varieties of intonarumori built in total, with different names.
Background
Russolo built ...
*
Loud music
Loud music is music that is played at a high volume, often to the point where it disturbs others and causes hearing damage. It may include music that is sung live, played with musical instruments, or with electronic media, such as Radio broadcas ...
*
Noise and vibration on maritime vessels
Noise and vibration on maritime vessels are not the same but they have the same origin and come in many forms. The methods to handle the related problems are similar, to a certain level, where most shipboard noise problems are reduced by controllin ...
*
Noise calculation
Noise calculation is the process of calculating the level of noise immission using the metric dB(A). Noise immission is created by noise sources (noise emission) of various types which are propagating noise into the environment. A single source w ...
*
Noise control
Noise control or noise mitigation is a set of strategies to reduce noise pollution or to reduce the impact of that noise, whether outdoors or indoors.
Overview
The main areas of noise mitigation or abatement are: transportation noise control, ...
*
Noise in music
In music, noise is variously described as unpitched, indeterminate, uncontrolled, loud, unmusical, or unwanted sound. Noise is an important component of the sound of the human voice and all musical instruments, particularly in unpitched perc ...
*
Noise music
*
Noise pollution
Noise pollution, also known as environmental noise or sound pollution, is the propagation of noise with ranging impacts on the activity of human or animal life, most of them are harmful to a degree. The source of outdoor noise worldwide is ma ...
*
Noise reduction
*
Silence
Silence is the absence of ambient audible sound, the emission of sounds of such low intensity that they do not draw attention to themselves, or the state of having ceased to produce sounds; this latter sense can be extended to apply to the c ...
*
Sound level meter
*
Soundscape
A soundscape is the acoustic environment as perceived by humans, in context. The term was originally coined by Michael Southworth, and popularised by R. Murray Schafer. There is a varied history of the use of soundscape depending on discipline, ...
*
The Hum
The Hum is a name often given to widespread reports of a persistent and invasive low-frequency humming, rumbling, or droning noise audible to many but not all people. Hums have been reported all over the world, including the United States, the Un ...
*
White noise
In signal processing, white noise is a random signal having equal intensity at different frequencies, giving it a constant power spectral density. The term is used, with this or similar meanings, in many scientific and technical disciplines ...
References
Further reading
*
*Urban, Felix (2016). ''Investigating sonic empowerment in urban cultures.'' Baden-Baden, Tectum.
*
External links
Guidelines for Community Noise, World Health Organization, 1999Audio Measuring Articles – ElectronicsMohr on Receiver Noise: Characterization, Insights & SurprisesNoise at workEuropean Agency for Safety and Health at Work (
EU-OSHA
The European Agency for Safety and Health at Work (EU-OSHA) is a decentralised agency of the European Union with the task of collecting, analysing and disseminating relevant information that can serve the needs of people involved in safety and h ...
)
Mountain & Plains ERC: A NIOSH Education and Research Center for Occupational & Environmental Health & SafetyUS National Institute for Occupational Safety and Health – Noise
Noise Pollution Clearing HouseIntroduction to the fundamentals of acoustic engineering
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