The Hum

The Hum

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The ‘Taos Hum’ is a low-pitched sound heard in numerous places worldwide, especially in the USA, UK, and northern europe. It is usually heard only in quiet environments, and is often described as sounding like a distant diesel engine. Since it has proven indetectable by microphones or VLF antennae, its source and nature is still a mystery.
In 1997 Congress directed scientists and observers from some of the most prestigious research institutes in the nation to look into a strange low frequency noise heard by residents in and around the small town of Taos, New Mexico. For years those who had heard the noise, often described by them as a “hum”, had been looking for answers. To this day no one knows the cause of the hum.

The Hum is sometimes prefixed with the name of a locality where the problem has been particularly publicized: e.g., the "Bristol Hum", the "Taos Hum" or the "Bondi 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.
In the Unsolved Mysteries segment called "Mystery Hum", a tape re-creation of the Taos Hum was used for this segment. Robert Stack reported that one of the "Hum sufferers" created the audio tape, mainly for the purpose in that particular segment. This was done since their audio equipment didn't pick up low-frequency sounds very well, and so that the show's viewers and other non-"Hum sufferers" would get an idea of what the actual auditory phenomenon sounded like.
On 15 November 2006, Dr. Tom Moir of the University of Massey in Auckland, New Zealand made a recording of the Auckland Hum and has published it on the university's website.The captured hum's power spectral density peaks at a frequency of 56 hertz. In 2009, the head of audiology at Addenbrooke's Hospital in Cambridge, Dr. David Baguley said that he believed people's problems with hum were based on the physical world about one-third of the time and the other two-thirds stemmed from people focusing too keenly on innocuous background sounds.


History

It was 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. 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.
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.


Some other possible explanations

-Tinnitus
-Spontaneous otoacoustic emissions
-Colliding ocean waves