As I'm typing this, it's a little after 4 a.m.. My often noisy neighbourhood is quiet, and the house is silent. There is a noise though, and it's not being made by any of the appliances in the house (believe me, I already shut off the power briefly to see if this was the cause..).
It seems to be coming from outside, but I can't tell where its source lies.
Imagine the noise of fairly distant machinery, a far-off generator, a plane engine in the distance, a car or small truck engine idling..it's a low, monotone droning. It's more audible at night, and some nights it's louder than others. Nobody else I know seems to be able to hear it.
I've been hearing it for years now, although I had nothing to attribute it to until I started researching it very recently- and I only did so because it finally annoyed me to the point I had to find out what it was all about!
Being the curious type I am, I've done a little reading into what might be going on..
I wondered if it was something to do with my health or hearing; something internally generated, or perhaps a side-effect of the Vertigo I was fairly recently diagnosed with..
But my hearing this strange noise predates my vertigo symptoms and my subsequent diagnosis, and there are seemingly no correlative symptoms that apply to Vertigo..
What I did find during my research was reports from people all over the world, thousands of them, who all describe the same sound, and report hearing it at similar times of day (or night), and who have similar complaints- that earplugs do nothing to stop it, but sometimes turning their heads rapidly, or performing a swallowing action, helps for a second..that it goes away or is less noticeable during the day..
It seems I may be one of the (approximately) 2-10% of the population that can hear "The Hum". Unfortunately. It's very annoying..
Reports of The Hum have been around for decades, with some apparently surfacing as far back as the 1940's. The phenomenon seems to have reached a peak over the last decade or so, but it's been disturbing the sleep of people all around the world for much longer.
There have been reports from many, many places- from Krasnoyarsk in Russia, to New Delhi, India; from the mountains of Nepal to the Sichuan province in China; from towns here in Australia, to far away Africa, and a great proliferation of reports from the U.K. and the U.S.A. In fact, it has puzzled and annoyed so many people that a worldwide database of reports has been compiled. You can view it here.
There was also an excellent research paper compiled by the same man responsible for the database; a Geo-scientist (and Hum hearer)by the name of David Deming, that you can read if you're interested.
For my mind, what's interesting is the diversity of people who have reported hearing the Hum- there are reports on the database from people of both genders, and of varying ages, nationalities, and occupations, living in many different kinds of terrains and locations- from coastal towns to mountains, from deserts to inland terrains. Equally interesting is that many have reported hearing it for years- just like me..
Speaking for myself personally, I first heard it about 9 years ago, whilst I was living in an inner-eastern suburb, (Doncaster), here in Victoria . At the time, being unaware of the fact that it was already a worldwide phenomenon, and having done no research on it, I put it down to noisy neighbours somewhere in my vicinity, who had the bass on their stereo turned up way too loud. I went on several night-time wanders trying to find those noisy neighbours, but never could do so..
Fast-forward about 6 years, and I had just moved to a bayside suburb called Frankston. The neighbourhood can be quite a noisy one, so after about a week of living here, I was unsurprised when, upon laying down in bed one night, I heard that same low-pitched bass hum. As time went on, I noticed that it would occur at times or on nights that didn't fit in with the "noisy stereo bass" hypothesis..after all, who would have their stereo on that loud at 3 a.m. on a Tuesday morning?? and why had nobody told them to turn it down??
I began to grow curious..which eventually led to the piece you are reading now.
A LITTLE HUM HISTORY
Reports of the Hum first began to surface in the media in the U.K. in 1970, although further anecdotal reports may exist from earlier decades.
Bristol, a port city in southwest England, has been plagued by the "Bristol Hum" since 1971. In 1973, when a woman there threatened suicide because of noises nobody else could hear, the local health-care authorities contacted a nearby university, and a noise expert, Dr. Joseph Hanlon, was sent out to check.
He could hear nothing, but he recorded that "nothing" on a cassette, and when he analysed the tape, he was surprised to find that there was a peak in the recorded frequencies of between 30 and 40 Hz.
In the 1970's, citizens in Rome, Italy, reported a repetitive throbbing noise that kept them awake at night. This sound apparently vanished and did not recur.
In another U.K. town- Largs, Scotland, a coastal town west of Glasgow, reports of the Hum began to surface in the 1980's. It appears to be one of several coastal towns in Scotland affected by the Hum since around the same time.
And reports kept flooding in from across the globe.
In 1992, media in the U.S. reported that some residents in Taos, New Mexico, had been bothered by a noise that many others couldn't hear. The reports began with a letter written by a woman to the local newspaper complaining about the sound. There was a flood of responses from others in the community who had also heard the sound but were reluctant to be the first to come forward..
As an interesting side-note, the Taos Hum was mentioned in an episode of "The X Files" called "Drive", in which one of the lead characters attributes it to ELF (extremely low frequency) electromagnetic fields.
In 1996 the Boston Herald reported a Hum heard by some residents in the small towns of Null and Nahant, both located on a peninsula about 13 kilometres east of Boston. In 1997 the Caledonian Record, a newspaper published in St. Johnsbury, Vermont, reported that some local residents had heard a humming sound, with one resident saying that he had been hearing it since 1989. The most recent incident in the U.S. to gain widespread media attention was the Kokomo (Indiana) Hum, which apparently began in 1999 and was first reported in 2001.
In Southwest Germany, reports of the Hum began appearing in the media in 2001. In 2002, the Times Colonist in Victoria, British Columbia, reported that a small number of residents had been hearing the Hum from as early as 1994.
In 2005, residents across the North Shore in Auckland, New Zealand, began to complain of hearing the Hum, and in 2009 the Sydney Morning Herald reported that residents of Bondi in New South Wales, Australia, had complained of hearing the Hum too.
So what is it that thousands of people worldwide are hearing? there have been a few hypotheses put forth, but no definitive answers. Let's have a look at some theories..
SOME HUM HYPOTHESES..
MECHANICAL ORIGINS:
Three of the Hum incidents were thought to have been traced to mechanical sources.
In the case of the Kokomo Hum, two suspected sources were a 36 Hz tone from a cooling tower at the local Chrysler-Daimler casting plant, and a 10 Hz tone from air compressor intake at the local Haynes International plant. After these devices were fixed though, reports of the Hum persisted.
There have actually been only two Hum incidents that have been definitively attributed to mechanical sources. The West Seattle Hum was traced to a vacuum pump used by CalPortland to offload cargo from ships. When the silencer on the pump was replaced, reports of the Hum ceased. The Hum in Wellington, New Zealand, reportedly vanished with the departure of a visiting frigate, and was attributed to that ship's diesel generator.
No mechanical sources have been proven to be the cause of a Hum in any other locations where it has been heard.
LORAN AND HAARP:
LORAN is an acronym for Long range Radio Navigation, and is a system first developed for military use in World War 2. The LORAN system consists of a network of powerful radio transmitters that continuously broadcast signals at a frequency of 100 kHz (10,000 Hz), and are used to find location by comparing signal arrival times from 3 or more transmitters.
There are some difficulties with the LORAN hypothesis though. If Broadcast towers were the source of the Hum, there should be a correlation between LORAN broadcast tower locations and Hum reports, however no such correlation has been found. There are certainly no towers in the part of Australia that I live in, and there have been only 2 reports listed thus far on the database from Hum hearers in the areas closest to the listed locations of LORAN towers in Australia.
HAARP is an acronym that stands for High frequency Active Auroral Research Program. The HAARP facility is located in the small town of Gakoma, 294 km northeast of Anchorage, Alaska. The research conducted in this program, which began around 1985, involves beaming energy into the ionosphere.
The rationale behind HAARP's research is that the transmission of high-frequency electromagnetic waves into the ionosphere can be used to control and alter the electric currents that exist there. Those currents can in turn then be used to generate Low Frequency waves for purposes such as submarine communications, terrestrial cross-section mapping, and (theoretically) even as a defense shield against incoming missiles.
HAARP is one of the preferred hypotheses for the Hum, but one small problem exists with this theory too- some reports of the Hum predate the beginning of the HAARP project.
MATING FISH:
In the case of some Hum reports in the U.K. and coastal U.S., it was thought that the Hum was being caused by the mating calls of the male Midshipman Fish (a type of Toadfish). The male of the species emits a low-frequency hum as a mating call to attract females.
However, the problem with this hypothesis lies in the fact that those who reported hearing the hum eventually attributed to the midshipman fish were occupants of houseboats, reporting hearing vibrations on the hull of their boats. It also can't explain the fact that Hum reports have come from inland or mountain areas too, far from the coastal regions the fish call home. There are certainly no midshipman fish anywhere near Doncaster, where I first heard the Hum!
TINNITUS:
Tinnitus is a medical condition characterised by a high-pitched ringing in the ears. When consulted, physicians would inevitably diagnose the Hum as being due to tinnitus, as there is no other option available to medical science.
In 1983, a physicist by the name of R.E. Walford conducted a series of tests on 48 people who heard the Hum and concluded that 10 of those "definitely have low-frequency tinnitus". His methodology was flawed, however. He assumed that any perceived sound associated with the Hum that could not be blocked by earmuffs must be internally generated, and therefore was tinnitus.
But if the hum is perhaps due to electromagnetic radiation, the earmuffs would have no effect. Walford attempted to control for radio-frequency hearing by wrapping subjects' heads in aluminium foil. This may be effective at blocking out EMF's in higher frequencies (i.e. microwaves), but would be completely ineffective at blocking out low frequency waves.
Hum-hearing symptoms are also quite different from classic tinnitus. Tinnitus is typically a high-frequency ringing sound, not a low-pitched rumble. According to a 1995 study, most individuals affected by tinnitus match the ringing in their ears to a tone between 3000-6000 Hz on a tone generator, and rarely, if ever, does a tinnitus sufferer match to a tone below 1000 Hz.
As the Hum has been mostly matched on a tone generator by hearers as being between 40 to 80 Hz, tinnitus seems to be unlikely- this is also indicated by the reports from some hearers that sometimes, often dependent upon distance from the usual location at which they hear it, the Hum can occasionally vanish for a short while, making it likely that this is an externally generated effect,
"HEARING" EXTREMELY LOW FREQUENCIES
So what exactly is it that people who hear the Hum are actually hearing? Perhaps we're not actually "hearing" anything. Some individuals, it seems, have a capability to detect extremely low-frequency electromagnetic waves to a greater degree than others, and as their brains have no other way of interpreting this, it is interpreted as sound. Deming calls this process electrophonics, and it could perhaps be considered a form of environmental sensitivity.
In the 1940's, people began to report hearing radar signals- and were suspected of being mentally ill- but research in subsequent years has established that some people are indeed capable of hearing radio waves. There is also some evidence in scientific literature that low-frequency electromagnetic waves can induce the perception of sound in some people.
In 1962, researcher Allan H. Frey published an interesting paper in the Journal of Applied Physiology, detailing an experiment he conducted using extremely low frequency electromagnetic energy to induce the perception of sound.
Frey detailed the results of the experiment, and also discussed effects that were induced upon subjects when the frequency levels were altered, stating;
"With appropriate modulation, the perception of various sounds can be induced in clinically deaf, as well as normal, human subjects at a distance of inches up to thousands of feet from the transmitter. With somewhat different transmitter parameters, we can induce the perception of severe buffeting of the head, without such apparent vestibular symptoms as dizziness or nausea. Changing transmitter parameters again, one can induce a "pins-and -needles" sensation."
(Frey 1962, Journal of Applied Physiology 17(4) p.689)
In another interesting study published in 2009 in the Journal of Low Frequency Noise, Vibration and Active Control, Professor Geoff Leventhall, a consultant in noise vibration and acoustics, mentions that there may exist, in some individuals, the capability to discern very low frequency sound (often called infrasound), and that this capability may be a consideration in the case of Hum hearers, stating:
"..as the complainants (in an unrelated case) had normal low frequency hearing, they will not have been detecting the noise through their ears and one is into a complex situation, common with many complaints of low frequency "hums", in which it is difficult to determine whether to assess the noise complaint in terms of low frequency tinnitus, or by the hypothesis of a rare and unknown detection mechanism of extraordinary sensitivity, which cannot be accounted for by the statistical extreme of the low frequency hearing threshold. The complainants described by Feldmann and Pitten may be in the category of "Hum sufferers".
(Leventhall 2009, JLFNVAC 28 (2), p.82)
A fun fact to end on here; anomalous sounds have also been reported coinciding with the advent of geomagnetic storms and the Aurora Borealis, and with the passage of large meteors through the Earth's atmosphere.
Basically, to sum it up, nobody knows what is causing the Hum. There have been various hypotheses profferred, but none of those are applicable across-the-board. Speaking for myself, I don't have any idea what it may be. But at least I now know it's not noisy neighbours!
What are YOUR thoughts? Have you had any experience with hearing the Hum, or do you know anyone that has, or does? Let me know in comments, I'd be very interested to hear others' thoughts!