The Hum
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225857003
2008-07-15T18:50:20Z
Wednesday Next
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{{Refimprove|date=July 2007}}
'''The Hum''' is a generic name for a series of phenomena involving a persistent and invasive low-frequency [[hum]]ming [[noise]] not audible to all people. Hums have been reported in various geographical locations. In some cases a source has been located. A well-known case was reported in [[Taos, New Mexico]], and thus the Hum is sometimes called the '''Taos Hum'''. Hums have been reported all over the world, especially in Europe. A Hum"on the Big Island of Hawaii, typically related to volcanic action, is heard in locations dozens of miles apart. The local Hawaiians also say the Hum is most often heard by men. The Hum is most often described as sounding somewhat like a distant idling [[diesel engine]]. Typically the Hum is difficult to detect with microphones, and its source and nature are hard to localize.
The Hum is sometimes prefixed with the name of a locality where the problem has been particularly publicized: e.g., the "[[Bristol]] Hum" or the "Taos Hum".
==Description==
The essential element that defines the Hum is what is perceived as a persistent low-frequency sound, often described as being comparable to that of a distant [[diesel engine]] idling, or to some similar low-pitched sound for which obvious sources (e.g., household appliances, traffic noise, etc.) have been ruled out.
Other elements seem to be significantly associated with the Hum, being reported by an important proportion of hearers, but not by all of them. Many people hear the Hum only, or much more, inside buildings as compared with outdoors. Many also perceive vibrations that can be felt through the body. Earplugs are reported as not decreasing the Hum. The Hum is often perceived more intensely during the night.
Some people perceive the Hum continuously, but others perceive it only during certain periods. For some people, the perceived Hum can represent a faint sound and a mild annoyance, while for others who perceive the Hum's sound and/or vibrations more intensely it represents a nuisance that can seriously interfere with daily activities. Common consequences include a lack of sleep, as the Hum can keep some people awake or wake them in the middle of the night. Such cases have given rise to the expression "Hum sufferers."
On 15th November 2006 Dr Tom Moir, of the [[University of Massey]] in [[Auckland]], [[New Zealand]], made a recording of the Auckland Hum and has [http://www.massey.ac.nz/~tjmoir/realhum.wav published it on the university's website]<ref>{{cite web|url=http://www.massey.ac.nz/~tjmoir/hum.html|title=Auckland North Shore Hum|accessdate=2006-11-24|last=Moir|first=Tom|date=2006-11-15|work=T.J.Moir Personal pages|publisher=University of Massey}}</ref><ref>{{cite news|first=Stephen|last=Hutcheon|title=Mystery humming sound captured|url=http://www.smh.com.au/articles/2006/11/17/1163266756133.html|work=Sydney Morning Herald|publisher=Fairfax|date=2006-11-17|accessdate=2006-11-24}}</ref>. The captured hum's [[power spectral density]] peaks at a [[frequency]] of 56 [[hertz]]<ref>{{cite news|first=Stephen|last=Hutcheon|title=Mystery noise is a real humdinger|url=http://www.smh.com.au/news/technology/mystery-noise-is-a-real-humdinger/2006/10/24/1161455714733.html|work=Sydney Morning Herald|publisher=Fairfax|date=2006-10-26|accessdate=2006-11-24}}</ref>.
==History==
It is during the 1990s that the Hum phenomenon began to be reported in [[North America]] and to be known to the American public, when a study by the University of New Mexico and the complaints from many citizens living near the town of [[Taos, New Mexico]], caught the attention of the media. However, in the 1970s and 1980s, a similar phenomenon had been the object of complaints from citizens, of media reports and of studies, mostly in the [[United Kingdom]] but also in other countries such as [[New Zealand]].<ref name="Massey University: Press release 11-OCT-2006">{{cite web|title=Researchers investigating things that go hum in the night|date=October 11, 2006|accessdate=2006-10-19|url=http://masseynews.massey.ac.nz/2006/Press_Releases/10-11-06.html|publisher=Massey University}}</ref> It is difficult to tell if the Hum reported in those earlier cases and the Hum that began to be increasingly reported in North America in the 1990s should be considered identical or of different natures. During the last decade, the Hum phenomenon has been reported in many other cities and regions in North America and [[Europe]] and in some other regions of the world.
==Explanations==
In the case of [[Kokomo, Indiana]], a city with heavy industries, the source of the hum was thought to have been traced to two sources. The first was a pair of fans in a [[cooling tower]] at the local [[DaimlerChrysler]] [[casting]] plant emitting a 36 Hz tone. The second was an [[air compressor]] intake at the Haynes International plant emitting a 10 Hz tone.<ref>{{cite journal|first=James P.|last=Cowan|title=The Kokomo Hum Investigation|volume=Acentech Incorporated|issue=Acentech Project No. 615411|publisher=City of Kokomo Board of Public Works and Safety|date=October 2003|url=http://www.milieuziektes.nl/ELF/KokomoHumFinalReport.pdf|accessdate=2006-11-27}}</ref><ref>{{cite news|title=Possible Source Found For Kokomo Hum: Hum Traced To Local Factory|work=TheIndyChannel.com|publisher=Internet Broadcasting Systems, Inc.|date=2003-09-19|url=http://www.theindychannel.com/news/2498604/detail.html|accessdate=2006-11-27}}</ref>
==Some possible explanations==
{{Unreferencedsection|date=January 2008}}
Some explanations of hums, for which no definitive source has been found, have been put forth. These include:
===Man-made noises===
High frequency attenuation of distant industrial sounds or stereo [[subwoofer]]s from homes, cars, and music venues. As sound moves through the atmosphere or ground, the high frequencies decrease in amplitude more rapidly than the low frequency ones, which subsequently travel greater distances. The low-frequency sounds can be amplified by walls and structural geometry, and sound like ambiguous rumblings or hums. Industrial machinery such as compressors, pumps and fans can also produce similar types of sounds. Although this is one of the explanations that first come to mind, ordinary microphones have failed to detect the Hum and investigations have failed to convincingly trace the Hum to such sources. Studies in the UK have addressed this issue.
===Infrasound made by geological events===
[[Infrasound]] from different possible sources, possibly [[geologic]] or [[plate tectonic]] in nature.
===Pulsed microwaves===
A phenomenon similar to the [[microwave auditory effect]] from pulsed microwave sources, possibly in combination with other factors. The thermoelastic mechanism may or may not be involved. Various types of electromagnetic sources could involve different physical or physiological mechanisms or a combination thereof. Some of the components of the electromagnetic environment, and examples of their possible combined effects, have been discussed in the annex to the report about the Hum by the experts hired by the city of Kokomo, [[Indiana]].
===Electromagnetic waves caused by meteors===
A variant of the [[audio frequency]] [[electromagnetic]] emissions generated upon the entry of a [[meteor]] and its disintegration in the upper atmosphere. The disintegration of larger meteors in the upper atmosphere is known to release [[megawatt]]s of power in the [[audio frequency]] range, primarily through the interaction of the resulting [[ionization trail]] with the [[Earth's magnetic field]]. See, for example [http://science.nasa.gov/headlines/y2001/ast26nov_1.htm Listening to Leonids] for a description of the meteor audio effect. (It is also speculated that the "solar wind" may be causing a similar effect to the "meteor audio effect.")
===Extremely low frequency communications systems===
Communication systems, such as [[communication with submarines|submarine communications systems]] that use [[extremely low frequency]] (ELF) radio transmissions. Proponents of this theory suggest the transmissions may somehow produce effects either directly or indirectly through mechanisms similar or different of those by which higher frequencies are detected.
===Ionospheric heating systems===
Large-scale effects of one or several of the [[Ionospheric heater|ionospheric heating projects]] in Norway, the U.S. or Russia, such as [[HAARP]] in Gakona, [[Alaska]].
===Tinnitus===
Generated by the body, the auditory or the nervous system, with no external stimulus. However, the theory that the Hum is actually [[tinnitus]] fails to explain why the Hum can only be heard at certain geographical locations. Some people who claim to hear the Hum say that it is worse indoors. This would lean towards tinnitus, as tinnitus is generally worse in places with less exterior sound. There may exist individual differences as to the threshold of perception of acoustic or non-acoustic stimuli, or other normal individual variations that could contribute to the fact that some people in the population perceive the Hum and others do not.
While hypothesized to be a form of low frequency tinnitus <ref>[http://amasci.com/hum/tinn2.txt AMASCI]</ref> such as the [[venous hum]], some sufferers claim it is not internal being worse inside their homes than outside. However, others insist that it is equally bad indoors and outdoors. More mystery is added as some only notice the Hum at home, while others hear it everywhere they go.
Some reports indicate that it is made worse by attempted soundproofing (e.g., [[double glazing]]), which only serves to decrease other environmental noise, thus making the Hum more apparent.
===The tensor tympani muscle making the eardrum tremble===
[[As of 2005]], a scientific hypothesis suggests the Hum originates on the eardrums of affected individuals by the [[tensor tympani]] muscle trembling. (The tensor tympani is a muscle within the inner ear for tightening the [[eardrum]].) The 40-page hypothesis can be read in German on the pages of the German Association for Research about the Hum, IGZAB (InteressenGemeinschaft Zur Aufklärung des Brummtonphänomens). See: http://www.IGZAB.de . See [[:de:Brummton-Phänomen]].
==The Hum in popular culture==
*The Taos Hum was featured on the TV show ''[[Unsolved Mysteries]]''.
*The Taos Hum was also mentioned, specifically the submarine radio theory, on the sixth season episode of [[The X-Files]], "[[Drive (The X-Files)|Drive]]."
*The Taos Hum was featured on the Science website [http://www.livescience.com/strangenews/top10_unexplained_phenomena.html LiveScience, Top 10 Unexplained Phenomena].
==See also==
*[[Bloop]]
*[[Slow Down (unidentified sound)|Slow Down]]
== References ==
<div class="references-small"><references/></div>
==External links==
* Mark Pilkington, ''[http://www.guardian.co.uk/life/farout/story/0,,1266037,00.html Humdinger]'', [http://www.guardian.co.uk/ The Guardian], July 22, 2004. - General background.
* The Guardian staff, ''[http://www.guardian.co.uk/g2/story/0,,576019,00.html What's that noise?]'', [http://www.guardian.co.uk/ The Guardian] October 18, 2001. - Article on the Largs Hum (Scotland) and the Hum in general.
* John Dawes, [http://homepages.tesco.net/~John.Dawes2/ The Hum] - Independent site, claims the hum is an electrical interference effect with buildings.
* William J. Beaty, [http://www.eskimo.com/~billb/hum/hum.html Taos Hum] - Independent site concerning mostly the Hum in Taos, New Mexico.
* Joe Mullins, [http://homepages.tesco.net/~John.Dawes2/taos.htm Summary of a study about the Taos Hum]
* [http://www.igzab.de Association for research about the Hum] - In German, with quite a few pages in English, including a FAQ about the Hum and the two parts of the Kokomo study.
* [http://groups.yahoo.com/group/humforum Internet discussion group about the Hum]
* [http://www.realworldmysteries.com/the_anomalous_3am_frequency.html The anomalous 3AM frequency]
*Samantha M. Friedrich, ''[http://www.zwire.com/site/index.cfm?newsid=16709874&BRD=1644&PAG=461&dept_id=10660&rfi=8 Resident irritated by 'hum']'', [http://www.zwire.com/site/news.cfm?brd=1644 The Thomaston Express], May 26, 2006. - Local Resident Experiencing the hum
* Toshiro Tanimoto (2008): Geophysics: Humming a different tune. In: ''Nature'' 452 : 539. [http://dx.doi.org/doi:10.1038/452539a]
[[Category:Noise|Hum]]
[[Category:Noise pollution|Hum]]
[[Category:Electricity]]
[[Category:New Mexico culture]]
[[Category:Unidentified sounds|Hum]]
[[bg:Таоско бучене]]
[[de:Brummton-Phänomen]]
[[fr:Bourdonnement]]
[[it:Il ronzio di Taos]]
[[fi:Humina]]