By James Donahue

Nobody can say exactly when folks in Taos, New Mexico, began hearing the disturbing humming noise. The story came to light when it began appearing in newspapers after about 1990, and a report made its way to Congress in 1993.

Some believe the sound was being detected as early as the 1970s.

The hum is usually described as low-frequency noise that sounds somewhat like a distant idling diesel engine. Oddly it is heard by some people in an area, but not all. Its low frequency has made it difficult to detect with electronic recording equipment and its source has been impossible to locate.

Some people say they cannot shut off the sound, but others say they “tune in” and hear it during certain times. Some people say the hum is so faint it has been but a mild annoyance. But others complain that it affects their sleep and is a constant distraction.

One interesting point found in a 1993 investigative report noted that “most hearers initially experienced the hum with an ‘abrupt beginning’ as if some device were switched on.” This caused some people to believe there was a connection between the hum, the military installations in and around New Mexico, and the Department of Defense.

Because Taos got a lot of press coverage, the phenomenon has been dubbed the Taos Hum. But the strange and bothersome sound has not been isolated just to Taos, New Mexico. Similar complaints have come from Kokomo, Indiana, various points on the Big Island of Hawaii, Bristol, United Kingdom, in Auckland, New Zealand and Bondi, Australia. There may be more.

The hum has been such an obtrusive yet unsolvable mystery it has captured not only newspaper space but a television documentary was presented in the Unsolved Mysteries series. Research teams have devoted hours of time attempting to find the source of the hums, but have only been able to come up with various theories.

In Kokomo, a city filled with heavy industry, the source was traced to one of two possible sources. One was a pair of fans in a cooling tower at a DaimlerChrysler casting plant that emitted a 36 Hz tone. The other was an air compressor intake at the Haynes International plant that gave off a tone at only 10 Hz. Neither theory has been proven, however.

Other possible explanations:

--The noises are man-made from industrial machinery, subwoofers and other devices. This theory suggests that the sounds may be coming from some distance. As sound moves through the atmosphere or the ground, high frequencies decrease more rapidly than the low frequencies which subsequently travel greater distances. These low-frequency sounds might sound like ambiguous rumblings or hums. Also industrial fans, compressors and pumps can produce these sounds as was discovered in Kokomo. Investigations, however, have failed to convincingly trace the hum to these sources.

--It is infrasound from geologic or plate tectonic movements in the Earth.

--The hums come from pulsed microwaves. The experts involved in studying the Kokomo hum suggested that various components of the “electromagnetic environment” and their combined effects may be involved in producing this low frequency noise.

--Electromagnetic waves caused by meteors. This is a relatively far-out variant of the audio frequency electromagnetic emissions theory. The idea is that it is generated by the entry of a meteor and its disintegration in the upper atmosphere. The force of the entry releases megawatts of power in an audio frequency range through an interaction with the Earth’s magnetic field. The problem is that meteors are not constantly striking the planet’s atmosphere.

--Extremely low frequency communication systems or (ELF) radio transmissions developed by the military for talking to submarines. It is suggested that some people can pick up on these transmissions.

--The military’s High Frequency Active Auroral Research Program (HAARP).

--Tinnitus, a disorder of the human nervous system that affects the auditory system. Victims hear certain noises that are generated from within the body. This theory, however, does not explain why the hum can be heard by victims in certain places and not in others.

--Spontaneous otoacoustic emissions. Like tinnitus, this is a condition that scientists say is generated from within the body. This condition is shared by about 30 percent of the people. These people typically hear a faint hissing or buzzing, especially if they are in a place of complete silence. It is a noise that people are so accustomed to hearing they rarely notice it. We believe that this sound is audible to nearly everyone although most people have failed to pay attention to it. But that is food for another story.

Dr. Nick Begich, well known for his research and writings concerning the government’s HAARP project designed to heat the outer atmosphere, has turned to an invention by Dr. Patrick Flanagan as a possible key to the hum issue. This device, the NeurophoneTM, is a low voltage, high frequency, amplitude modulated radio oscillator that acts on the human skin to send sound to the brain. It allows the listener to “hear” without using the ear canal.

Begich and Flanagan note that in our modern world, we are surrounded by low frequency devices, all operating at about 60 Hz. They say it is possible that this concentration of frequency may be resonating with the skin, and in some people getting a direct neural link from the skin to the brain.

They may have hit on something. Researcher Joe Mullins of the University of New Mexico notes that all of the cordless cell phones, computers, television, radio and other devices are “building up the background of electronic noise.”

Mullins notes that “whether that’s the cause of the hum, we don’t know, but we can’t write it off.”