Mysterious Sounds: The Hum

The mystery of The Hum. The first reports of mysterious, monotonous droning noises began in the 1940s and 50s, but the most well known case was the Bristol Hum, heard by about 800 people in Bristol, England in 1979. Scotland followed suit with reports of a strange hum in the 1980s, then Taos, New Mexico put the U.S. on the Hum map.

Apparently as much as 2% of people in “Hum prone” areas, known as “sufferers,” are plagued by The Hum. They claim to be troubled by a persistent humming noise that has been described by some sufferers as a truck driving up hill in low gear, never reaching the top. A low frequency resonance.

But what could The Hum be?

A 2003 study by consultant Geoff Leventhall, an expert in acoustics and president of The Institute of Acoustics, states:

The Hum is the name given to a low frequency noise which is causing persistent complaints, but often cannot be traced to a single, or any, source. If a source is located, the problem moves into the category of engineering noise control and is no longer “the Hum”, although there may be a long period between first complaint and final solution.

Is the Hum the result of a social effect or suggestion? Leventhall’s study explains,

The Hum is widespread, affecting scattered individuals, but periodically a Hum focus arises where there are multiple complaints within a town or area. There has been the Bristol Hum (England), Largs Hum (Scotland), Copenhagen Hum (Denmark), Vancouver Hum (Canada), Taos Hum (New Mexico USA), Kokomo Hum (Indiana USA) etc. A feature of these Hums is that they have been publicised in local and national press, so gathering a momentum which otherwise might not have occurred. The concepts of memetics are applicable here.

Memes, a term coined by Richard Dawkins in his book The Selfish Gene, are ideas, behaviors or styles that spread through a culture person to person. Wikipedia explains memes well, “A meme acts as a unit for carrying cultural ideas, symbols, or practices that can be transmitted from one mind to another through writing, speech, gestures, rituals, or other imitable phenomena.”

If an individual’s experience is not corroborated by others in the immediate area at the time, or detected with equipment and subsequently it may be subjective, specific to the individual, and could possibly be previously undetected effects of tinnitus, or otoacoustic emissions, noticed after the individual was made aware of the phenomenon through exposure to a meme, through the media or hearsay.

Possible explanations for The Hum include tinnitus, spontaneous otoacoustic emissions (SOE, sounds generated by the ears themselves), and infrasound created by nearby machinery, industrial processes, highway traffic, gas lines, or natural sources, including colliding ocean waves.

In the case of tinnitus and SOE, the specific sound would not be detectable by equipment or anyone else, only known to the subject.

According to an article on NBC News, “Generally, the Hum is only heard indoors, and it’s louder at night than during the day.” The article goes on to state, “It’s also more common in rural or suburban environments; reports of a hum are rare in urban areas.”

This would hold true for internal or external causes of The Hum, since the humming is faint enough to be masked by some ambient noise near the subject.

This author has actually experienced The Hum, but it seems to follow me around, and is intermittent, so it may be the effect of low frequency tinnitus brought on by either muscle tension in the neck or sinus pressure associated with seasonal allergies.

Other Mysterious Cases of The Hum
Whatever the cause it is a strange effect, especially at night, when things are quite. And especially in colder months when we close our windows. The Hum takes on an ominous quality, and it’s easy to imagine some clandestine scenario like massive machinery tunneling its way through the earth, digging subterranean research facilities, secret infrasound guidance systems for submarines, or maybe something stranger.

The McCalla Hum, for example. In 2011, residents of McCalla, Alabama, woke to a strange noise described by some as distant sirens, helicopters or locusts. They could not pinpoint a source, for when they walked in a direction which seemed to be its origin, the sound would then appear to come from behind them.

Strange indeed, but Samford University biology professor, Lawrence J. Davenport, Ph.D., insists that what the residents of McCalla heard were 13 year cicadas.

What other natural phenomena might explain The Hum?

A Review of Published Research on Low Frequency Noise and its Effects
The Hum – Wikipedia, the free encyclopedia
Sourcing the Taos Hum
NBC News
Infrasound Laboratory