Array ( [0] => {{short description|Branch of physics involving mechanical waves}} [1] => {{other uses}} [2] => [[File:Lindsay's Wheel of Acoustics.svg|thumb|alt=Lindsay's Wheel of acoustics|upright=1.75|Lindsay's Wheel of Acoustics, which shows fields within acoustics]] [3] => [4] => '''Acoustics''' is a branch of [[physics]] that deals with the study of [[mechanical wave]]s in gases, liquids, and solids including topics such as [[vibration]], [[sound]], [[ultrasound]] and [[infrasound]]. A scientist who works in the field of acoustics is an '''acoustician''' while someone working in the field of acoustics technology may be called an [[Acoustical engineering|acoustical engineer]]. The application of acoustics is present in almost all aspects of modern society with the most obvious being the audio and [[noise control]] industries. [5] => [6] => [[Hearing (sense)|Hearing]] is one of the most crucial means of survival in the animal world and [[speech]] is one of the most distinctive characteristics of human development and culture. Accordingly, the science of acoustics spreads across many facets of human society—music, medicine, architecture, industrial production, warfare and more. Likewise, animal species such as songbirds and frogs use sound and hearing as a key element of mating rituals or for marking territories. Art, craft, science and technology have provoked one another to advance the whole, as in many other fields of knowledge. [[Robert Bruce Lindsay]]'s "Wheel of Acoustics" is a well accepted overview of the various fields in acoustics.{{citation|title=What is acoustics?|url=https://acoustics.byu.edu/what-is|website=Acoustical Research Group|archive-url=https://web.archive.org/web/20210416224358/https://acoustics.byu.edu/what-is|publisher=Brigham Young University|access-date=2021-04-16|archive-date=2021-04-16|url-status=live}} [7] => [8] => == History == [9] => [10] => === Etymology === [11] => The word "acoustic" is derived from the [[Ancient Greek|Greek]] word ἀκουστικός (''akoustikos''), meaning "of or for hearing, ready to hear"[http://www.perseus.tufts.edu/cgi-bin/ptext?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3D%233396 Akoustikos] {{Webarchive|url=https://web.archive.org/web/20200123045124/http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3D%233396&redirect=true |date=2020-01-23 }} Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', at Perseus and that from ἀκουστός (''akoustos''), "heard, audible",[http://www.perseus.tufts.edu/cgi-bin/ptext?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3D%233397 Akoustos] {{Webarchive|url=https://web.archive.org/web/20200123045124/http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3D%233397&redirect=true |date=2020-01-23 }} Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', at Perseus which in turn derives from the verb ἀκούω(''akouo''), "I hear".[http://www.perseus.tufts.edu/cgi-bin/ptext?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3D%233399 Akouo] {{Webarchive|url=https://web.archive.org/web/20200123045114/http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3D%233399&redirect=true |date=2020-01-23 }} Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', at Perseus [12] => [13] => The Latin synonym is "sonic", after which the term '''sonics''' used to be a synonym for acoustics{{cite book|author=Kenneth Neville Westerman|title=Emergent Voice|url=https://books.google.com/books?id=xNQrAAAAMAAJ|year=1947|publisher=C. F. Westerman|access-date=2016-02-28|archive-date=2023-03-01|archive-url=https://web.archive.org/web/20230301145219/https://books.google.com/books?id=xNQrAAAAMAAJ|url-status=live}} and later a branch of acoustics. [[Frequency|Frequencies]] above and below the [[Audio frequency|audible range]] are called "[[Ultrasound|ultrasonic]]" and "[[infrasonic]]", respectively. [14] => [15] => === Early research in acoustics === [16] => [[Image:Harmonic partials on strings.svg|thumb|The [[Fundamental frequency|fundamental]] and the first 6 [[overtone]]s of a vibrating string. The earliest records of the study of this phenomenon are attributed to the philosopher [[Pythagoras]] in the 6th century BC.]] [17] => [18] => In the 6th century BC, the ancient Greek philosopher [[Pythagoras]] wanted to know why some [[Interval (music)|combinations of musical sounds]] seemed more beautiful than others, and he found answers in terms of numerical ratios representing the [[harmonic]] [[overtone series]] on a string. He is reputed to have observed that when the lengths of vibrating strings are expressible as ratios of integers (e.g. 2 to 3, 3 to 4), the tones produced will be harmonious, and the smaller the integers the more harmonious the sounds. For example, a string of a certain length would sound particularly harmonious with a string of twice the length (other factors being equal). In modern parlance, if a string sounds the note C when plucked, a string twice as long will sound a C an octave lower. In one system of [[musical tuning]], the tones in between are then given by 16:9 for D, 8:5 for E, 3:2 for F, 4:3 for G, 6:5 for A, and 16:15 for B, in ascending order.C. Boyer and [[Uta Merzbach|U. Merzbach]]. ''A History of Mathematics.'' Wiley 1991, p. 55. [19] => [20] => [[Aristotle]] (384–322 BC) understood that sound consisted of compressions and rarefactions of air which "falls upon and strikes the air which is next to it...",{{cite web|title=How Sound Propagates|url=http://press.princeton.edu/chapters/s9912.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://press.princeton.edu/chapters/s9912.pdf |archive-date=2022-10-09 |url-status=live|publisher=Princeton University Press|access-date=9 February 2016}} (quoting from Aristotle's ''Treatise on Sound and Hearing''){{Cite book|last=Whewell, William, 1794–1866.|title=History of the inductive sciences : from the earliest to the present times. Volume 2|isbn=978-0-511-73434-2|location=Cambridge|oclc=889953932|page=295}} a very good expression of the nature of [[wave]] motion. ''[[On Things Heard]]'', generally ascribed to [[Strato of Lampsacus]], states that the pitch is related to the frequency of vibrations of the air and to the speed of sound.{{Cite book|title=Greek musical writings|date=2004|publisher=Cambridge University Press|others=Barker, Andrew|isbn=0-521-38911-9|edition=1st pbk.|location=Cambridge|oclc=63122899|page=98}} [21] => [22] => In about 20 BC, the Roman architect and engineer [[Vitruvius]] wrote a treatise on the acoustic properties of theaters including discussion of interference, echoes, and reverberation—the beginnings of [[architectural acoustics]].ACOUSTICS, Bruce Lindsay, Dowden – Hutchingon Books Publishers, Chapter 3 In Book V of his {{lang|la|[[De architectura]]}} (''The Ten Books of Architecture'') Vitruvius describes sound as a wave comparable to a water wave extended to three dimensions, which, when interrupted by obstructions, would flow back and break up following waves. He described the ascending seats in ancient theaters as designed to prevent this deterioration of sound and also recommended bronze vessels of appropriate sizes be placed in theaters to resonate with the fourth, fifth and so on, up to the double octave, in order to resonate with the more desirable, harmonious notes.Vitruvius Pollio, [https://archive.org/details/vitruviustenbook00vitr_0 ''Vitruvius, the Ten Books on Architecture''] (1914) Tr. Morris Hickey Morgan BookV, Sec.6–8[[wikiquote:Vitruvius#Book V|Vitruvius]] article @WikiquoteErnst Mach, Introduction to ''The Science of Mechanics: A Critical and Historical Account of its Development'' (1893, 1960) Tr. Thomas J. McCormack [23] => [24] => During the [[Islamic Golden Age|Islamic golden age]], Abū Rayhān al-Bīrūnī (973-1048) is believed to have postulated that the speed of sound was much slower than the speed of light.{{cite journal|arxiv = 1312.7288|title = The Science of Al-Biruni|first = Amelia Carolina|last = Sparavigna|s2cid = 119230163|doi = 10.18483/ijSci.364|volume = 2|issue = 12|date = December 2013|journal = International Journal of Sciences|pages = 52–60|url = https://www.ijsciences.com/pub/pdf/V220131220.pdf|bibcode = 2013arXiv1312.7288S|access-date = 2018-11-04|archive-date = 2018-07-21|archive-url = https://web.archive.org/web/20180721215451/https://www.ijsciences.com/pub/pdf/V220131220.pdf|url-status = live}}{{cite web|url = http://www-groups.dcs.st-and.ac.uk/history/Biographies/Al-Biruni.html|title = Abu Arrayhan Muhammad ibn Ahmad al-Biruni|publisher = School of Mathematics and Statistics, University of St. Andrews, Scotland|date = November 1999|access-date = 2018-08-20|archive-url = https://web.archive.org/web/20161121101131/http://www-groups.dcs.st-and.ac.uk/history/Biographies/Al-Biruni.html|archive-date = 2016-11-21|url-status = dead}} [25] => [26] => [[File:Amman Roman theatre.jpg|thumb|left|Principles of acoustics have been applied since ancient times: a [[Roman theatre (structure)|Roman theatre]] in the city of [[Amman]]]] [27] => [28] => The physical understanding of acoustical processes advanced rapidly during and after the [[Scientific Revolution]]. Mainly [[Galileo Galilei]] (1564–1642) but also [[Marin Mersenne]] (1588–1648), independently, discovered the complete [[Mersenne's laws|laws of vibrating strings]] (completing what Pythagoras and Pythagoreans had started 2000 years earlier). Galileo wrote "Waves are produced by the [[vibration]]s of a sonorous body, which spread through the air, bringing to the tympanum of the [[ear]] a stimulus which the mind interprets as sound", a remarkable statement that points to the beginnings of physiological and psychological acoustics. Experimental measurements of the [[speed of sound]] in air were carried out successfully between 1630 and 1680 by a number of investigators, prominently Mersenne. Meanwhile, [[Isaac Newton|Newton]] (1642–1727) derived the relationship for wave velocity in solids, a cornerstone of [[physical acoustics]] ([[Philosophiæ Naturalis Principia Mathematica|Principia]], 1687). [29] => [30] => === Age of Enlightenment and onward === [31] => Substantial progress in acoustics, resting on firmer mathematical and physical concepts, was made during the eighteenth century by [[Leonhard Euler|Euler]] (1707–1783), [[Joseph-Louis Lagrange|Lagrange]] (1736–1813), and [[Jean le Rond d'Alembert|d'Alembert]] (1717–1783). During this era, continuum physics, or field theory, began to receive a definite mathematical structure. The wave equation emerged in a number of contexts, including the propagation of sound in air.{{Cite book|title=Acoustics : an introduction to its physical principles and applications|last=Pierce, Allan D.|date=1989|publisher=Acoustical Society of America|isbn=0-88318-612-8|edition=1989|location=Woodbury, N.Y.|oclc=21197318}} [32] => [33] => In the nineteenth century the major figures of mathematical acoustics were [[Helmholtz]] in Germany, who consolidated the field of physiological acoustics, and [[John Strutt, 3rd Baron Rayleigh|Lord Rayleigh]] in England, who combined the previous knowledge with his own copious contributions to the field in his monumental work ''The Theory of Sound'' (1877). Also in the 19th century, Wheatstone, Ohm, and Henry developed the analogy between electricity and acoustics. [34] => [35] => The twentieth century saw a burgeoning of technological applications of the large body of scientific knowledge that was by then in place. The first such application was [[Wallace Clement Sabine|Sabine]]'s groundbreaking work in architectural acoustics, and many others followed. Underwater acoustics was used for detecting submarines in the first World War. [[Sound recording]] and the telephone played important roles in a global transformation of society. Sound measurement and analysis reached new levels of accuracy and sophistication through the use of electronics and computing. The ultrasonic frequency range enabled wholly new kinds of application in medicine and industry. New kinds of transducers (generators and receivers of acoustic energy) were invented and put to use. [36] => [37] => == Definition == [38] => {{multiple image [39] => | align = right [40] => | direction = horizontal [41] => | header = [[Jay Pritzker Pavilion]] [42] => | header_align = left/right/center [43] => | header_background = [44] => | footer = At [[Jay Pritzker Pavilion]], a [[LARES]] system is combined with a zoned [[sound reinforcement system]], both suspended on an overhead steel trellis, to synthesize an indoor acoustic environment outdoors. [45] => | footer_align = left/right/center [46] => | footer_background = [47] => | image1 = 20070919 Pritzker Pavilion from stage.JPG [48] => | width1 = 178 [49] => | image2 = 20070919 Pritzker Pavilion speakers.JPG [50] => | width2 = 100 [51] => }} [52] => [53] => Acoustics is defined by [[ANSI/ASA S1.1-2013]] as "(a) Science of [[sound]], including its production, transmission, and effects, including biological and psychological effects. (b) Those qualities of a room that, together, determine its character with respect to auditory effects." [54] => [55] => The study of acoustics revolves around the generation, propagation and reception of mechanical waves and vibrations. [56] => [57] => ::'''[[File:Cause-effect diagram for acoustics.svg|The fundamental acoustical process]]''' [58] => [59] => The steps shown in the above diagram can be found in any acoustical event or process. There are many kinds of cause, both natural and volitional. There are many kinds of transduction process that convert energy from some other form into sonic energy, producing a sound wave. There is one fundamental equation that describes sound wave propagation, the [[acoustic wave equation]], but the phenomena that emerge from it are varied and often complex. The wave carries energy throughout the propagating medium. Eventually this energy is transduced again into other forms, in ways that again may be natural and/or volitionally contrived. The final effect may be purely physical or it may reach far into the biological or volitional domains. The five basic steps are found equally well whether we are talking about an [[earthquake]], a submarine using sonar to locate its foe, or a band playing in a rock concert. [60] => [61] => The central stage in the acoustical process is wave propagation. This falls within the domain of physical acoustics. In [[fluid]]s, sound propagates primarily as a [[Longitudinal wave|pressure wave]]. In solids, mechanical waves can take many forms including [[longitudinal waves]], [[transverse waves]] and [[surface waves]]. [62] => [63] => Acoustics looks first at the pressure levels and frequencies in the sound wave and how the wave interacts with the environment. This interaction can be described as either a [[diffraction]], [[Interference (wave propagation)|interference]] or a [[Reflection (physics)|reflection]] or a mix of the three. If several [[Transmission medium|media]] are present, a [[refraction]] can also occur. Transduction processes are also of special importance to acoustics. [64] => [65] => == Fundamental concepts == [66] => === Wave propagation: pressure levels === [67] => {{Main|Sound pressure}} [68] => [69] => [[Image:Oh No Girl Spectrogram 2.jpg|thumb|[[Spectrogram]] of a young girl saying "oh, no"]] [70] => In fluids such as air and water, sound waves propagate as disturbances in the ambient pressure level. While this disturbance is usually small, it is still noticeable to the human ear. The smallest sound that a person can hear, known as the [[Absolute threshold of hearing|threshold of hearing]], is nine orders of magnitude smaller than the ambient pressure. The [[loudness]] of these disturbances is related to the [[sound pressure level]] (SPL) which is measured on a logarithmic scale in decibels. [71] => [72] => === Wave propagation: frequency === [73] => {{further|Sound#Frequency}} [74] => [75] => Physicists and acoustic engineers tend to discuss sound pressure levels in terms of frequencies, partly because this is how our [[ears]] interpret sound. What we experience as "higher pitched" or "lower pitched" sounds are pressure vibrations having a higher or lower number of cycles per second. In a common technique of acoustic measurement, acoustic signals are sampled in time, and then presented in more meaningful forms such as octave bands or time frequency plots. Both of these popular methods are used to analyze sound and better understand the acoustic phenomenon. [76] => [77] => The entire spectrum can be divided into three sections: audio, ultrasonic, and infrasonic. The audio range falls between 20 [[Hertz|Hz]] and 20,000 Hz. This range is important because its frequencies can be detected by the human ear. This range has a number of applications, including speech communication and music. The ultrasonic range refers to the very high frequencies: 20,000 Hz and higher. This range has shorter wavelengths which allow better resolution in imaging technologies. Medical applications such as [[Medical ultrasonography|ultrasonography]] and elastography rely on the ultrasonic frequency range. On the other end of the spectrum, the lowest frequencies are known as the infrasonic range. These frequencies can be used to study geological phenomena such as earthquakes. [78] => [79] => Analytic instruments such as the [[spectrum analyzer]] facilitate visualization and measurement of acoustic signals and their properties. The [[spectrogram]] produced by such an instrument is a graphical display of the time varying pressure level and frequency profiles which give a specific acoustic signal its defining character. [80] => [81] => === Transduction in acoustics === [82] => [[Image:3.5 Inch Speaker.jpg|thumb|An inexpensive low fidelity 3.5 inch '''driver''', typically found in small radios]] [83] => A [[transducer]] is a device for converting one form of energy into another. In an electroacoustic context, this means converting sound energy into electrical energy (or vice versa). Electroacoustic transducers include [[loudspeaker]]s, [[microphone]]s, [[particle velocity]] sensors, [[hydrophone]]s and [[sonar]] projectors. These devices convert a sound wave to or from an electric signal. The most widely used transduction principles are [[electromagnetism]], [[electrostatics]] and [[piezoelectricity]]. [84] => [85] => The transducers in most common loudspeakers (e.g. [[woofer]]s and [[tweeter]]s), are electromagnetic devices that generate waves using a suspended diaphragm driven by an electromagnetic [[voice coil]], sending off pressure waves. [[Electret microphone]]s and [[condenser microphone]]s employ electrostatics—as the sound wave strikes the microphone's diaphragm, it moves and induces a voltage change. The ultrasonic systems used in medical ultrasonography employ piezoelectric transducers. These are made from special ceramics in which mechanical vibrations and electrical fields are interlinked through a property of the material itself. [86] => [87] => ==Acoustician== [88] => [89] => An acoustician is an expert in the science of sound.{{cite book|last=Schwarz|first=C|title=Chambers concise dictionary|year=1991}} [90] => [91] => ===Education=== [92] => There are many types of acoustician, but they usually have a [[Bachelor's degree]] or higher qualification. Some possess a degree in acoustics, while others enter the discipline via studies in fields such as [[physics]] or [[engineering]]. Much work in acoustics requires a good grounding in [[Mathematics]] and [[science]]. Many acoustic scientists work in research and development. Some conduct basic research to advance our knowledge of the perception (e.g. [[hearing]], [[psychoacoustics]] or [[neurophysiology]]) of [[speech]], [[music]] and [[noise]]. Other acoustic scientists advance understanding of how sound is affected as it moves through environments, e.g. [[underwater acoustics]], architectural acoustics or [[structural acoustics]]. Other areas of work are listed under subdisciplines below. Acoustic scientists work in government, university and private industry laboratories. Many go on to work in [[Acoustical Engineering]]. Some positions, such as [[Faculty (academic staff)]] require a [[Doctor of Philosophy]]. [93] => [94] => == Subdisciplines == [95] => [96] => ===Archaeoacoustics=== [97] => [[File:Gibraltar 2015 10 19 1964 (24110677143).jpg|thumb|St. Michael's Cave]] [98] => [[Archaeoacoustics]], also known as the archaeology of sound, is one of the only ways to experience the past with senses other than our eyes.{{Cite web|url=https://www.dailygrail.com/2016/01/archaeoacoustics-listening-to-the-sounds-of-history/|title=Archaeoacoustics: Listening to the Sounds of History|last=Clemens|first=Martin J.|date=2016-01-31|website=The Daily Grail|language=en-AU|access-date=2019-04-13|archive-date=2019-04-13|archive-url=https://web.archive.org/web/20190413223442/https://www.dailygrail.com/2016/01/archaeoacoustics-listening-to-the-sounds-of-history/|url-status=live}} Archaeoacoustics is studied by testing the acoustic properties of prehistoric sites, including caves. Iegor Rezkinoff, a sound archaeologist, studies the acoustic properties of caves through natural sounds like humming and whistling.{{Cite web|url=http://www.atlasobscura.com/articles/archaeoacoustics|title=With Archaeoacoustics, Researchers Listen for Clues to the Prehistoric Past|last=Jacobs|first=Emma|date=2017-04-13|website=Atlas Obscura|language=en|access-date=2019-04-13|archive-date=2019-04-13|archive-url=https://web.archive.org/web/20190413221942/https://www.atlasobscura.com/articles/archaeoacoustics|url-status=live}} Archaeological theories of acoustics are focused around ritualistic purposes as well as a way of echolocation in the caves. In archaeology, acoustic sounds and rituals directly correlate as specific sounds were meant to bring ritual participants closer to a spiritual awakening. Parallels can also be drawn between cave wall paintings and the acoustic properties of the cave; they are both dynamic. Because archaeoacoustics is a fairly new archaeological subject, acoustic sound is still being tested in these prehistoric sites today. [99] => [100] => ===Aeroacoustics=== [101] => {{main|Aeroacoustics}} [102] => [103] => [[Aeroacoustics]] is the study of noise generated by air movement, for instance via turbulence, and the movement of sound through the fluid air. This knowledge is applied in [[acoustical engineering]] to study how to quieten [[aircraft]]. Aeroacoustics is important for understanding how wind [[musical instrument]]s work.{{cite book|last=da Silva|first=Andrey Ricardo|title=Aeroacoustics of Wind Instruments: Investigations and Numerical Methods|year=2009|publisher=VDM Verlag|isbn=978-3639210644}} [104] => [105] => ===Acoustic signal processing=== [106] => {{see also|Audio signal processing}} [107] => [108] => Acoustic signal processing is the electronic manipulation of acoustic signals. Applications include: [[active noise control]]; design for [[hearing aid]]s or [[cochlear implant]]s; [[echo cancellation]]; [[music information retrieval]], and perceptual coding (e.g. [[MP3]] or [[Opus (audio format)|Opus]]).{{cite journal|last=Slaney|first=Malcolm|author-link=Malcolm Slaney|author2=Patrick A. Naylor|title=Trends in Audio and Acoustic Signal Processing|journal=[[ICASSP]]|date=2011}} [109] => [110] => ===Architectural acoustics=== [111] => {{main|Architectural acoustics}} [112] => [[Image:Symphony hall boston.jpg|thumb|right|[[Symphony Hall, Boston]], where auditorium acoustics began]] [113] => [114] => Architectural acoustics (also known as building acoustics) involves the scientific understanding of how to achieve good sound within a building.{{cite book|last=Morfey|first=Christopher|title=Dictionary of Acoustics|year=2001|publisher=Academic Press|pages=32}} It typically involves the study of speech intelligibility, speech privacy, music quality, and vibration reduction in the built environment.{{cite book|last=Templeton|first=Duncan|title=Acoustics in the Built Environment: Advice for the Design Team|year=1993|publisher=Architectural Press|isbn=978-0750605380}} Commonly studied environments are hospitals, classrooms, dwellings, performance venues, recording and broadcasting studios. Focus considerations include room acoustics, airborne and impact transmission in building structures, airborne and structure-borne noise control, noise control of building systems and electroacoustic systems [https://asastudents.org/about/what-are-tcs/]. [115] => [116] => ===Bioacoustics=== [117] => {{main|Bioacoustics}} [118] => [119] => [[Bioacoustics]] is the scientific study of the hearing and calls of animal calls, as well as how animals are affected by the acoustic and sounds of their habitat.{{cite web |url=http://www.bioacoustics.info/ |title=Bioacoustics - the International Journal of Animal Sound and its Recording |publisher=Taylor & Francis |access-date=31 July 2012 |archive-date=5 September 2012 |archive-url=https://web.archive.org/web/20120905120546/http://www.bioacoustics.info/ |url-status=live }} [120] => [121] => ===Electroacoustics=== [122] => {{See also|Audio Engineering|Sound reinforcement system}} [123] => [124] => This subdiscipline is concerned with the recording, manipulation and reproduction of audio using electronics.{{cite web|last=Acoustical Society of America|title=Acoustics and You (A Career in Acoustics?)|url=http://asaweb.devcloud.acquia-sites.com/education_outreach/careers_in_acoustics|access-date=21 May 2013|archive-url=https://web.archive.org/web/20150904010934/http://asaweb.devcloud.acquia-sites.com/education_outreach/careers_in_acoustics|archive-date=2015-09-04|url-status=dead}} This might include products such as [[mobile phone]]s, large scale [[public address]] systems or [[virtual reality]] systems in research laboratories. [125] => [126] => ===Environmental noise and soundscapes=== [127] => {{main|Environmental noise}} [128] => {{see also|Noise pollution|Noise control}} [129] => [130] => Environmental acoustics is concerned with noise and vibration caused by railways,{{cite book|editor-last=Krylov|editor-first=V.V. |title=Noise and Vibration from High-speed Trains|year=2001|publisher=Thomas Telford|isbn=9780727729637}} road traffic, aircraft, industrial equipment and recreational activities.{{cite book|last=World Health Organisation|title=Burden of disease from environmental noise|year=2011|publisher=WHO|isbn=978-92-890-0229-5|url=http://www.euro.who.int/__data/assets/pdf_file/0008/136466/e94888.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.euro.who.int/__data/assets/pdf_file/0008/136466/e94888.pdf |archive-date=2022-10-09 |url-status=live}} The main aim of these studies is to reduce levels of environmental noise and vibration. Research work now also has a focus on the positive use of sound in urban environments: [[soundscape]]s and [[tranquility]].{{cite book|last=Kang|first=Jian|title=Urban Sound Environment|year=2006|publisher=CRC Press|isbn=978-0415358576}} [131] => [132] => ===Musical acoustics=== [133] => {{main|Musical acoustics}} [134] => [[File:Brodmann 41 42.png|thumb|The [[primary auditory cortex]], one of the main areas associated with superior pitch resolution]] [135] => Musical acoustics is the study of the physics of acoustic instruments; the [[audio signal processing]] used in electronic music; the computer analysis of music and composition, and the perception and [[cognitive neuroscience of music]].{{cite web|last=Technical Committee on Musical Acoustics (TCMU) of the Acoustical Society of America (ASA)|url=http://www.public.coe.edu/~jcotting/tcmu/|title=ASA TCMU Home Page|access-date=22 May 2013|archive-url=https://web.archive.org/web/20010613120620/http://www.public.coe.edu/~jcotting/tcmu/|archive-date=2001-06-13|url-status=dead}} [136] => [137] => ===Noise=== [138] => The goal this acoustics sub-discipline is to reduce the impact of unwanted sound. Scope of noise studies includes the generation, propagation, and impact on structures, objects, and people. [139] => * Innovative model development [140] => * Measurement techniques [141] => * Mitigation strategies [142] => * Input to the establishment of standards and regulations [143] => Noise research investigates the impact of noise on humans and animals to include work in definitions, abatement, transportation noise, hearing protection, Jet and rocket noise, building system noise and vibration, atmospheric sound propagation, [[soundscape]]s, and low-frequency sound. [144] => [145] => ===Psychoacoustics=== [146] => Many studies have been conducted to identify the relationship between acoustics and [[cognition]], or more commonly known as [[psychoacoustics]], in which what one hears is a combination of perception and biological aspects.{{Cite journal|last1=Iakovides|first1=Stefanos A.|last2=Iliadou|first2=Vassiliki TH|last3=Bizeli|first3=Vassiliki TH|last4=Kaprinis|first4=Stergios G.|last5=Fountoulakis|first5=Konstantinos N.|last6=Kaprinis|first6=George S.|date=2004-03-29|title=Psychophysiology and psychoacoustics of music: Perception of complex sound in normal subjects and psychiatric patients|journal=Annals of General Hospital Psychiatry|volume=3|issue=1|pages=6|doi=10.1186/1475-2832-3-6 |doi-access=free|issn=1475-2832|pmc=400748|pmid=15050030}} The information intercepted by the passage of sound waves through the ear is understood and interpreted through the brain, emphasizing the connection between the mind and acoustics. Psychological changes have been seen as brain waves slow down or speed up as a result of varying auditory stimulus which can in turn affect the way one thinks, feels, or even behaves.{{Cite web|url=http://memtechacoustical.com/psychoacoustics/|title=Psychoacoustics: The Power of Sound|date=2016-02-11|website=Memtech Acoustical|language=en-US|access-date=2019-04-14|archive-date=2019-04-15|archive-url=https://web.archive.org/web/20190415003935/http://memtechacoustical.com/psychoacoustics/|url-status=live}} This correlation can be viewed in normal, everyday situations in which listening to an upbeat or uptempo song can cause one's foot to start tapping or a slower song can leave one feeling calm and serene. In a deeper biological look at the phenomenon of psychoacoustics, it was discovered that the central nervous system is activated by basic acoustical characteristics of music.{{Cite journal|last=Green|first=David M.|date=1960|title=Psychoacoustics and Detection Theory|journal=The Journal of the Acoustical Society of America|language=en|volume=32|issue=10|pages=1189–1203|doi=10.1121/1.1907882|issn=0001-4966|bibcode=1960ASAJ...32.1189G}} By observing how the central nervous system, which includes the brain and spine, is influenced by acoustics, the pathway in which acoustic affects the mind, and essentially the body, is evident. [147] => [148] => ===Speech=== [149] => {{main|Speech}} [150] => [151] => Acousticians study the production, processing and perception of speech. [[Speech recognition]] and [[Speech synthesis]] are two important areas of speech processing using computers. The subject also overlaps with the disciplines of physics, [[physiology]], [[psychology]], and [[linguistics]].{{cite web|title = Technical Committee on Speech Communication|url = https://tcscasa.org/|publisher = Acoustical Society of America|access-date = 2018-11-04|archive-date = 2018-11-05|archive-url = https://web.archive.org/web/20181105110754/https://tcscasa.org/|url-status = live}} [152] => [153] => ===Structural Vibration and Dynamics=== [154] => {{main|Vibration}} [155] => [156] => Structural acoustics is the study of motions and interactions of mechanical systems with their environments and the methods of their measurement, analysis, and control [https://tcsaasa.org/]. There are several sub-disciplines found within this regime: [157] => * [[Modal Analysis]] [158] => * [[Material characterization]] [159] => * [[Structural health monitoring]] [160] => * Acoustic [[Metamaterials]] [161] => * [[Friction Acoustics]] [162] => [163] => Applications might include: [[ground vibrations]] from railways; [[vibration isolation]] to reduce vibration in operating theatres; studying how vibration can damage health ([[vibration white finger]]); [[vibration control]] to protect a building from earthquakes, or measuring how structure-borne sound moves through buildings.{{cite web|title=Structural Acoustics & Vibration Technical Committee |url=https://tcsaasa.org/ |url-status=live |archive-url=https://web.archive.org/web/20180810080424/http://tcsaasa.org/ |archive-date= 10 August 2018 }} [164] => [165] => ===Ultrasonics=== [166] => [[File:CRL Crown rump lengh 12 weeks ecografia Dr. Wolfgang Moroder.jpg|thumb|Ultrasound image of a fetus in the womb, viewed at 12 weeks of pregnancy (bidimensional-scan)]] [167] => {{main|Ultrasound}} [168] => Ultrasonics deals with sounds at frequencies too high to be heard by humans. Specialisms include medical ultrasonics (including medical ultrasonography), [[sonochemistry]], [[ultrasonic testing]], material characterisation and underwater acoustics ([[sonar]]).{{cite book|last=Ensminger|first=Dale|title=Ultrasonics: Fundamentals, Technologies, and Applications|year=2012|publisher=CRC Press|pages=1–2}} [169] => [170] => ===Underwater acoustics=== [171] => {{main|Underwater acoustics}} [172] => [173] => Underwater acoustics is the scientific study of natural and man-made sounds underwater. Applications include [[sonar]] to locate [[submarines]], [[Whale vocalization|underwater communication by whales]], [[climate change]] monitoring by measuring [[sea temperature]]s acoustically, [[sonic weapons]],{{cite journal |author=D. Lohse, B. Schmitz & M. Versluis |s2cid=4429684 |title=Snapping shrimp make flashing bubbles |journal=[[Nature (journal)|Nature]] |volume=413 |issue=6855 |year=2001 |pages=477–478 |doi=10.1038/35097152 |pmid=11586346|bibcode = 2001Natur.413..477L }} and marine bioacoustics.{{cite web|last=ASA Underwater Acoustics Technical Committee |title=Underwater Acoustics |url=http://www.apl.washington.edu/projects/ASA-UATC/index.php |access-date=22 May 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130730104616/http://www.apl.washington.edu/projects/ASA-UATC/index.php |archive-date=30 July 2013 }} [174] => [175] => ==Acoustic Conferences== [176] => *[[InterNoise]] [177] => *[[NoiseCon]] [178] => *[[Forum Acousticum]] [179] => *[[SAE Noise and Vibration Conference and Exhibition]] [180] => [181] => ==Professional societies== [182] => *[[Acoustical Society of America|The Acoustical Society of America]] (ASA) [183] => *[[Australian Acoustical Society]] (AAS) [184] => *[[European Acoustics Association|The European Acoustics Association]] (EAA) [185] => *[[Institute of Electrical and Electronics Engineers]] (IEEE) [186] => *[[Institute of Acoustics (United Kingdom)|Institute of Acoustics]] (IoA UK) [187] => *[[Audio Engineering Society|The Audio Engineering Society]] (AES) [188] => *[[American Society of Mechanical Engineers|American Society of Mechanical Engineers, Noise Control and Acoustics Division]] (ASME-NCAD) [189] => *[[International Commission for Acoustics]] (ICA) [190] => *[[American Institute of Aeronautics and Astronautics|American Institute of Aeronautics and Astronautics, Aeroacoustics ]] (AIAA) [191] => *[[International Computer Music Association]] (ICMA) [192] => [193] => ==Academic journals== [194] => {{main category|Acoustics journals}} [195] => * Acoustics | An Open Access Journal from MDPI [196] => * [[Acoustics Today]] [197] => * Acta Acustica united with Acustica [198] => * Advances in Acoustics and Vibration [199] => * [[Applied Acoustics]] [200] => * Building Acoustics [201] => * [[IEEE]] Transacions on Ultrasonics, Ferroelectrics, and Frequency Control [202] => * [[Journal of the Acoustical Society of America]] (JASA) [203] => * Journal of the Acoustical Society of America, Express Letters (JASA-EL) [204] => * Journal of the [[Audio Engineering Society]] [205] => * [[Journal of Sound and Vibration]] (JSV) [206] => * Journal of Vibration and Acoustics [[American Society of Mechanical Engineers]] [207] => * MDPI Acoustics [208] => * Noise Control Engineering Journal [209] => * SAE International Journal of Vehicle Dynamics, Stability and NVH [210] => * [[Ultrasonics (journal)]] [211] => * Ultrasonics Sonochemistry [212] => * Wave Motion [213] => [214] => == See also == [215] => {{div col|colwidth=}} [216] => [217] => *[[Outline of acoustics]] [218] => *[[Acoustic attenuation]] [219] => *[[Acoustic emission]] [220] => *[[Acoustic engineering]] [221] => *[[Acoustic impedance]] [222] => *[[Acoustic levitation]] [223] => *[[Acoustic location]] [224] => *[[Acoustic phonetics]] [225] => *[[Acoustic streaming]] [226] => *[[Acoustic tags]] [227] => *[[Acoustic thermometry]] [228] => *[[Acoustic wave]] [229] => *[[Audiology]] [230] => *[[Auditory illusion]] [231] => *[[Diffraction]] [232] => *[[Doppler effect]] [233] => *[[Fisheries acoustics]] [234] => *[[Friction acoustics]] [235] => *[[Helioseismology]] [236] => *[[Lamb wave]] [237] => *[[Linear elasticity]] [238] => *''[[The Little Red Book of Acoustics]]'' (in the UK) [239] => *[[Longitudinal wave]] [240] => *[[Musicology]] [241] => *[[Music therapy]] [242] => *[[Noise pollution]] [243] => *[[One-Way Wave Equation]] [244] => *[[Phonon]] [245] => *[[Picosecond ultrasonics]] [246] => *[[Rayleigh wave]] [247] => *[[Shock wave]] [248] => *[[Seismology]] [249] => *[[Sonification]] [250] => *[[Sonochemistry]] [251] => *[[Soundproofing]] [252] => *[[Soundscape]] [253] => *[[Sonic boom]] [254] => *[[Sonoluminescence]] [255] => *[[Surface acoustic wave]] [256] => *[[Thermoacoustics]] [257] => *[[Transverse wave]] [258] => *[[Wave equation]] [259] => {{div col end}} [260] => [261] => == References == [262] => {{Reflist}} [263] => [264] => == Further reading == [265] => * {{cite book | vauthors=Attenborough K, Postema M |title=A pocket-sized introduction to acoustics |date=2008 |publisher=Kingston upon Hull: University of Hull |url=https://hal.archives-ouvertes.fr/hal-03188302/document| isbn=978-90-812588-2-1 |doi=10.5281/zenodo.7504060}} [266] => * {{cite book |vauthors=Benade AH |title=Fundamentals of Musical Acoustics |date=1976 |publisher=Oxford University Press |location=New York |isbn=978-0-19-502030-4|oclc=2270137 |url=https://archive.org/details/fundamentalsofmu0000bena | url-access=registration |ref=none}} [267] => * {{cite book |vauthors=Biryukov SV, Gulyaev YV, Krylov VV, Plessky VP |title=Surface Acoustic Waves in Inhomogeneous Media |date=1995 |publisher=Springer |location=Heidelberg |isbn=978-3-540-58460-5 |url=https://books.google.com/books?id=WR-jfwMnDYYC |ref=none}} [268] => * {{cite book |veditors=Crocker MJ|title=Encyclopedia of Acoustics |date=1997 |publisher=Wiley |location=Hoboken |isbn=|oclc=441305164 |ref=none|url=https://archive.org/details/encyclopediaofac0003unse_l4l2/page/n5/mode/2up}} [269] => * {{cite book |vauthors=Falkovich G |title=Fluid Mechanics, a short course for physicists |date=2011 |location=Cambridge|publisher=Cambridge University Press |isbn=978-1-107-00575-4 |url=http://www.weizmann.ac.il/complex/falkovich/fluid-mechanics |ref=none}} [270] => * {{cite book |vauthors=Fahy FJ, Gardonio P |title=Sound and Structural Vibration: Radiation, Transmission and Response |date=2007 |publisher=Academic Press |location=Amsterdam |isbn=978-0-08-047110-5 |edition=2nd |url=https://books.google.com/books?id=caelfFmWC28C |ref=none}} [271] => * {{cite book | vauthors=Junger MC, Feit D |title=Sound, Structures and Their Interaction |date=1986 |publisher=MIT Press |location=Cambridge |edition=2nd |url=http://mitpress.mit.edu/books/sound-structures-and-their-interaction |archive-url=https://web.archive.org/web/20140605030702/http://mitpress.mit.edu/books/sound-structures-and-their-interaction |archive-date=2014-06-05 |ref=none}} [272] => * {{cite book | vauthors=Kinsler LE |title=Fundamentals of Acoustics |url=https://archive.org/details/fundamentalsofac00kins/page/n5/mode/2up|date=1999 |publisher=Wiley |location=Hoboken |isbn=978-04718-4-789-2 |edition=4th |url-access=registration|ref=none}} [273] => * {{cite book | vauthors=Mason WP, Thurston RN | url=http://librarum.org/book/2513/1 | title=Physical Acoustics | year=1981 | publisher=Springer | location=Heidelberg| archive-url=https://web.archive.org/web/20131225161706/http://librarum.org/book/2513/1 | archive-date=2013-12-25 }} [274] => * {{cite book | vauthors=Morse PM, Ingard KU | year=1986 | title=Theoretical Acoustics | location=Princeton | publisher=Princeton University Press | isbn=0-691-08425-4}} [275] => * {{cite book | vauthors=Pierce AD | year=1989 | title=Acoustics: An Introduction to its Physical Principles and Applications | publisher=Acoustical Society of America |location= Melville | isbn=0-88318-612-8}} [276] => * {{cite book | vauthors=Raichel DR | year=2006 | title=The Science and Applications of Acoustics | edition=2nd | publisher=Springer | location=Heidelberg | isbn=0-387-30089-9}} [277] => * {{Cite book [278] => | last1=Lord Rayleigh [279] => | title=The Theory of Sound [280] => | publisher=Dover [281] => | place=New York [282] => | year=1894 [283] => | isbn=978-0-8446-3028-1 [284] => }} [285] => * {{cite book | vauthors=Skudrzyk E | year=1971 | title=The Foundations of Acoustics: Basic Mathematics and Basic Acoustics | publisher=Springer |location=Heidelberg}} [286] => * {{Cite book [287] => | vauthors=Stephens RW, Bate AE [288] => | title=Acoustics and Vibrational Physics [289] => | edition=2nd [290] => | publisher=Edward Arnold [291] => | place=London [292] => | year=1966 [293] => }} [294] => * {{Cite book [295] => | vauthors= Wilson CE [296] => | title=Noise Control [297] => | edition=Revised [298] => | publisher=Krieger [299] => | place=Malabar [300] => | year=2006 [301] => | isbn=978-1-57524-237-8 [302] => | oclc=59223706 [303] => }} [304] => [305] => == External links == [306] => {{Commons category|Acoustics}} [307] => {{wikisource|The New Student's Reference Work/Acoustics|Acoustics}} [308] => {{wikibooks|Acoustics}} [309] => * [http://www.icacommission.org/ International Commission for Acoustics] [310] => * [https://euracoustics.org European Acoustics Association] [311] => * [http://acousticalsociety.org/ Acoustical Society of America] [312] => * [http://www.inceusa.org/ Institute of Noise Control Engineers] [313] => * [http://www.ncac.com/ National Council of Acoustical Consultants] [314] => * [http://www.ioa.org.uk/ Institute of Acoustic in UK] [315] => * [https://www.acoustics.org.au/ Australian Acoustical Society (AAS) ] [316] => {{Physics-footer}} [317] => {{Acoustics}} [318] => {{Authority control}} [319] => {{Portal bar|Physics}} [320] => [321] => [[Category:Acoustics| ]] [322] => [[Category:Sound]] [] => )
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Acoustics

Acoustics is the branch of physics that deals with the study of sound and its behavior in various mediums. It focuses on the generation, transmission, and reception of sound waves and how they interact with different objects and environments.

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It focuses on the generation, transmission, and reception of sound waves and how they interact with different objects and environments. Acoustics plays a vital role in many fields, including music, communication, architecture, and medicine. The Wikipedia page on acoustics provides a comprehensive overview of this scientific discipline. It begins by explaining the essential concepts and principles of acoustics, such as the nature of sound waves, frequency, amplitude, and intensity. It delves into the properties of sound and how it is measured and analyzed. The page then explores the different branches of acoustics, including architectural acoustics, musical acoustics, and physical acoustics. It discusses how sound behaves in spaces and how it can be controlled and manipulated to enhance the quality of musical performances and optimize room acoustics. It also covers the physics behind musical instruments and their sound production. The article further explores the applications of acoustics in various fields. It discusses the use of acoustics in communication systems, such as telephones and hearing aids. It also explores the role of acoustics in medical imaging, ultrasound technology, and sonar systems used for underwater exploration. Additionally, the Wikipedia page provides information on the history of acoustics, highlighting key contributors and breakthroughs in the field. It mentions notable figures such as Pythagoras, Leonardo da Vinci, and Hermann von Helmholtz, who made significant contributions to the study of acoustics. In conclusion, the Wikipedia page on acoustics serves as a valuable resource for anyone interested in understanding the science of sound. It covers the fundamental principles, branches, applications, and historical aspects of acoustics, providing a comprehensive overview for readers.

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