Can You Hear the Hum?

An exploration of the mysterious rumble that some people hear all over the world.

by Brian Dunning

Filed under General Science, Urban Legends

Skeptoid #90
March 4, 2008
Podcast transcript | Listen | Subscribe
Also available in Chinese

Close the windows, turn off the electricity, and be very quiet: We're listening for the Hum, a worldwide phenomenon in which a distant rumbling sound can be heard in some places by some people. No single cause has ever been found. The Hum is infamous in some of its most noted locations: The Taos Hum in New Mexico, The Bristol Hum in England, the Auckland Hum in New Zealand, the Kokomo Hum in Indiana. In these places, some 2-10% of the population can hear the rumble. It's described as sounding like a distant diesel engine idling. Some people hear it better outdoors; some people hear it better indoors; some people hear it higher up on the second story and others lower down in the basement. In some places, more men hear it than women. In others, more women hear it. Some Hums are heard more often by older people, and some by younger people. For some people, earplugs help — indicating that it's an actual audible sound; for others, they don't — indicating that it's not. Explanations ranging from insect noise to meteors to secret government projects abound, but no explanation is satisfying.

So what exactly does this Hum sound like? Let's listen to one. A number of people have made synthesized versions of the Hum with the cooperation of sufferers, sort of like an audible police sketch of a suspect. Dr. Tom Moir in New Zealand has done some research on the Auckland Hum, and has collected an actual audio recording, of which I'll now play a few seconds. It's really low frequency, so you might not be able to hear it on computer speakers. Here goes: [play sample]

Some people I spoke with did cast doubt on the authenticity of this recording, saying that nobody has ever successfully managed to record the Hum, and that this sample sounds identical to some of the synthesized versions out there. However, when presented for purely illustrative purposes, this recording does give an accurate representation of the general consensus for what the Hum sounds like. In reponse to my email inquiry, Dr. Moir replied:

The recording on my web page is for real. Having said that, this does not imply some great mystery since very low frequency sound can travel for vast distances.

If the Hum can be recorded by audio equipment, that proves that it's an actual audio phenomenon. But others have failed to record anything, and have put forth other possible explanations. Dr. David Deming of the University of Oklahoma has probably done the most scholarly research of the Hum, though he's quite forthright in the lack of testable evidence. Hum research has had, thus far, to rely heavily on anecdotal reports and personal stories. But Dr. Deming has managed to conclude that the most probable explanation is that some people have been found to be able to hear radio waves.

Now before you spring for your tinfoil hat, allow me to read a snippet from the conclusion of the best paper on this phenomenon, Human Auditory Perception of Pulsed Radiofrequency Energy, by Drs. Joe Elder and C.K. Chou of the Motorola Florida Research Laboratories:

Human perception of pulses of RF radiation is a well-established phenomenon that is not an adverse effect. RF-induced sounds are similar to other common sounds such as a click, buzz, hiss, knock or chirp. Furthermore, the phenomenon can be characterized as the perception of subtle sounds because, in general, a quiet environment is required for the sounds to be heard. To hear the sounds, individuals must be capable of hearing high frequency acoustic waves in the kHz range and the exposure to pulsed RF fields must be in the MHz range. The experimental weight-of-evidence does not support direct stimulation of the central nervous system by RF pulses.

I did not find this research to be a convincing explanation for the Hum, and the reason is that the perceived sound that subjects reported was radically different from descriptions of the Hum. Apparently, in these cases where powerful RF pulses can induce a perceived sound in some humans, the frequency of the perceived sound is related to the size of the head and mass of the brain of the listener; it is not related to whatever signal may be contained in the RF. Adult humans who can perceive RF will seem to hear a sound around 13 kHz. That's a really high pitched sound; too high for a lot of people to hear. This is a 13 kHz tone: [play sample] Notice that no matter how you break that up into clicks, pops, or chirps, it's never going to sound anything like the Hum. Thus, the evidence we have about humans hearing sounds caused by RF is that it's a very poor candidate for the Hum.

And just what might these radio sources be? The most frequently blamed suspect is the US government's High Frequency Active Auroral Research Program (HAARP) in Alaska. This is a research project that transmits RF straight up into the ionosphere, at approximately 1/10,000 the power of the sun's normal electromagnetic radiation. So far it has been able to produce a tiny artificial aurora, detectable by sensitive instruments but not by the naked eye; and also Very Low Frequency (VLF) waves at .1 Hz, which are otherwise difficult to create. Mentioning HAARP and the Hum in the same sentence appears to imply some kind of connection, and of course any government technology project raises suspicion among the paranoid; but I see no plausible connection between the two. There's been no correlation between HAARP and the Hum in either time or space. Reports from Hum sufferers did not increase when HAARP began only recently, and localized Hum phenomena have never been near the HAARP site either before or since it began. And, as discussed previously, the potential acoustic effects of RF radiation are completely dissimilar from the Hum.

Others blame cell phone networks or LORAN, the radio-based predecessor to the Global Positioning System. These candidates have the same evidenciary problems as HAARP and their only real support comes from the crowd that promotes the pseudoscience of modern electromagnetic fields as health hazards.

Mass hysteria has also been put forward as a possible cause. If the Hum is some kind of hysteria, it's certainly not a mass one. Very few people hear the Hum, even in the hotbed areas. Psychoacoustics and auditory hallucinations are not unheard of, and have been correlated with other physiological effects of stress. I did a fair amount of searching around the web to see if I could find any cases of Hum sufferers being treated with psychotherapy or other stress reduction, but did not find anything; so there does not yet appear to be any data supporting this hypothesis. But, given the total number of people who have experienced the Hum over the years, it seems probable that at least some of those cases could be explained by psychophysiology.

If you go to your doctor to complain about the Hum, the most likely diagnosis you'll get is tinnitus. This is the ringing in the ears that everyone gets at some point, and is often associated with ear infections, tube blockages or even head injuries. I've had this probably about as much as most people, and to me it sounds nothing like the Hum. However, by yawning or by tightening the tensor tympani muscle inside my ear, I can induce a loud, low-frequency rumble. It's hard to describe exactly how I do it, but I can make it last for maybe 30 or 40 seconds before the muscle fatigues. When I do this, it sounds exactly like the Hum. It's also gotten stuck a few times when I've had a cold or blown my nose too hard, and when it goes by itself, it tickles and is really annoying, and I end up with this rumble in my head for a while. It's not hard to think that some people may have this condition chronically, and since this is the exact sound described by Hum sufferers, it's virtually certain that some variation on this condition is the explanation for some of them.

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The city of Kokomo, Indiana hired a firm, Acentech Incorporated, to find the source of the Kokomo Hum and suggest solutions. The lead investigator, James P. Cowan, did find two sources of industrial noise that were likely candidates: Some cooling fans at the local DaimlerChrysler factory emitting a 36 Hz tone, and an air compressor at the Hayes International plant emitting a 10 Hz tone. These were alleviated, but complaints did not cease altogether. Cowan's investigation was thorough and he did conclude that there was probably something else causing at least some of these complaints.

So how do you wrap up a question like the Hum? When you assemble all the research and reports, you get a lot of footnotes, some data, some hypotheses, but mostly a giant pile of question marks. I think it does all lead to one conclusion that is pretty certain: There is no Hum. At least, not a single worldwide phenomenon that we can lump together and call the Hum. There are many people all over the world who perceive a low rumble under certain conditions. Many of them are probably hearing an actual audible sound from some relatively mundane, yet undiscovered, source. Some are probably suffering from a problem with tinnitus or the tensor tympani muscle. Some are probably experiencing an auditory hallucination. Some may be hearing an undiscovered geophysical phenomenon. And there are probably some hearing something from a cause that nobody has even hypothesized about yet. But there are also many people experiencing similar things: Different types of sounds, strange lights, unexplained feelings. We don't call all of those the Hum too. Whatever the various causes of these peoples' experiences is, it seems clear that there is no one quantifiable Hum that adequately explains all these diverse reports. Thus, anyone doing "Hum research" is really pursuing something that probably does not exist. Yes, it's possible that most of these cases share the same cause, but it's much more likely that very few of them do.

Brian Dunning

© 2008 Skeptoid Media, Inc. Copyright information

References & Further Reading

Cowan, James. "Kokomo Hum." Acentech Consultants. Acentech, 1 Oct. 2003. Web. 19 Nov. 2009. <>

Deming, David. "The Hum: An Anomalous Sound Heard Around the World." Journal of Scientific Exploration. 1 Oct. 2004, Volume 18, Number 4: 571-595.

Editors. "Who, What, Why: Why is The Hum such a mystery?" BBC News. British Broadcasting Corporation, 13 Jun. 2011. Web. 25 Nov. 2012. <>

Elder, J.A., Chou, C.K. "Auditory response to pulsed radiofrequency energy." Bioelectromagnetics. 21 Mar. 2003, Volume 24, Issue S6: S162-S173.

Moir, T.J. "Auckland North Shore Hum." T.J. Moir Personal Web Page. Massey University, 1 Mar. 2007. Web. 19 Nov. 2009. <>

Mullins, Joe H., Poteet, Horace. "A perceived low-frequency sound in Taos, New Mexico." Journal of the Acoustical Society of America. 1 Nov. 1994, Volume 96, Issue 5: 3334-3334.

Reference this article:
Dunning, B. "Can You Hear the Hum?" Skeptoid Podcast. Skeptoid Media, Inc., 4 Mar 2008. Web. 18 Apr 2015. <>


10 most recent comments | Show all 496 comments

There are new cell towers all around the citys mostly near highways.
Twice within this last week (7-7-14) I've heard a high pitched noise in the early morning that sounds like a machine humming. Also a week ago my husband and I were driving south out of the valley in AZ and when we had driven just past the serious of small mountains on I10 we both had a high pitched sound that we heard and felt in our heads. For me it hurt suddenly and horribly! As soon as we got past unmarked city limits the pain suddenly stopped. Is there some kind of testing going on with these new cell towers.
Is there a connection with the smart dust swarms that blows through my yard every day after 5pm? I now look for the strange chem trails after I'm bitten by these swarms of non-bugs. They literally look like tiny white dust particles. I've heard the high pitched sound in the evening around 8pm a few months ago and heard strange noises like tiny popping sounds and then bitten by the 'smart dust' 15 seconds later. I did research on this 'smart dust' and it seems to be controlled. I'm not kidding!

ann nonymous, arizona
July 7, 2014 8:07am

I've been hearing the hum since my early 20s I personally don't feel it is an audible sensation. I can usually disrupt the hum with any other sound, thus I sleep with an electric fan going 365 nights a year. Recently I have discovered the hum is intermittent, whereas it used to be constant.
The most irritating thing to be is when people who can't hear it scoff at me and believe I'm making it up.

Darling, Ohio
August 2, 2014 7:07am

I hear the 13k tone alot when i'm somewhere quiet it. I've not heard the other sound yet i did play the file so i'll try to keep my ears open for that one.

Daniel, UK
September 15, 2014 9:54pm

Where i live, about 5 miles out of town I am able to hear the Hum. The ground here is mostly sand, clay and limestone, really no hard solid rock to speak of. When i do hear it its usually on a clear day or night, no rain or anything. I decided to check up on it as I was awake about 5am and am hearing the hum very clearly. Mostly I turn on something to drown it out like a fan but tonight i can hear it over the fan still. I have noticed when I do go to another location I will not hear it then when I return home I hear it. It is not everyday i hear it , sometimes its going for a full week then stops a few days then again. Haven't been keeping track of it but I do remember when I started to hear it maybe 5 or 6 years back. The audio clip does match it though, the sound drops and rises as if air pressure is affecting it. I do hear very high pitch, once during an hearing examination for a job the nurse did a double take at my results unbelieving. Perhaps it is something that only a select few can hear, if it was in our heads we would hear it everywhere we went but that isn't the case, it is localized. Could the government be "creating" global warming as a vehicle to push certain things? Correct me if I'm wrong, the array spoken of does raise the temperature high in the atmosphere causing it to rise. Someone has to be controlling this or else it wouldn't stop right? The EPA answers to no department above itself save the president?

Ronnie, Greensboro, Florida
October 28, 2014 8:21am

Firstly, how long has the capital city of Australia been in the Coral Sea Islands? When I signed up for your emails it kept defaulting to that.

It's my guess that some of those who hear "the hum" in some of their house rooms but not in others, and not outside, are hearing noise conducted by water, gas or sewer lines from pumps, or possibly slight vibration in power lines attached to the house caused by wind. I've recently had some experience of this. A hissing sound in the toilet vanished when a leak in the water mains several metres away was repaired. Not audible in the laundry, kitchen or at the garden water taps. According to the plumber, it is pretty common to only hear it in only one place in the house.

For those hearing it outside, I suspect wind again. I've heard an almost imperceptible breeze faintly whistling at an empty beer bottle on a fence post, so why should not buildings resonate at lower frequencies. Just a guess.

I have tinnitus, a constant tone about 1200 Hz at a guess, more than 1000 and less than 2000 at any rate. Nothing like the reported hum.

Ken, Canberra
December 3, 2014 11:04pm

I am a member of The World Council. We finished a 12 year investigation of the use of passive covert radar, specifically cellular radar (called celldar) using various kinds of signals, with a deeper focus on microwave communications. As of early 2015 we have begun crafting antennas and experimenting with advanced spectrometers and magnetometers to report specifics. The two main things we uncovered from 2002 to 2014 were this.

While "the hum" may be specific as to what is causing it locally, as in any kind of phenomenon, machinery, freak of nature, what have you, the mass increase in this infrasonic "humming" now torturing millions, literally, is being caused by the insane amount of communications being done using microwaves. Everything from high speed internet, including use of smart phones, the overbuild of cell towers and the introduction of billions of smart meters and the microwave repeaters necessary for their operation are big parts of the problem.

That is ONE thing. Again we're not talking about some localized hum people have been hearing for decades at certain locations, we're talking about people everywhere feeling these infrasonic pulsations.

Two, and this is the really bad part. All kinds of passive covert radar is being ran now under the guise of national security. This rage of perversion will, every time, cause problems. This is a nightmare yet to be told. It will not end well. Politics are involved, so your governments will not help you, AND are guilty.

todd west, cartersville
January 5, 2015 6:47pm


I am a 35 years old Romanian woman currently living in Spain.
I can hear the hum since a child. It never bothered me. In fact I considered it to be relaxing.
The first time I acknoledged it, I thought that it was caused by our small city railway station / train.
I still hear it in Spain with the difference that currently I can hear it a lot more and it lasts for time. I even considered to study it and write down the result of the Hum ´´sessions´´ on a 10 hour frame. Each Hum ´´session´´ lasts difefrently, they have different intensity and they certainly are not equals in terms in intensity and time.
I have never been on psychiatric treatment, I do not drink at all and I do not take drugs. (I am something like a monk :-) )

In my opinion - and I must admit I am not a cientist - it must be some kind of a noise of the planet Earth (magnetic field maybe). The fact that some persons hear it and some dont´ does not mean anything. I mean, animals do hear a lot more things than humans . Some living creatures perceive more than others and that is all.
I am not worried about the Hum...
Who knows? Myabe it brings good news after all!!

Have a nice day to you all,

Iulia, Madrid / Spain
January 16, 2015 3:25am

Moved into a new home within a quarter mile of water/sewer plant. From first night I realized I made a mistake. Noise emanated from plant. What realtors claimed was RO plant is large capacity water and sewer plant. Gotcha! Didn't think plant mattered a quarter mile away. Wrong! Plant off gasses from water and sewer operations. Haven't slept well since moving in due to the hum. The plant devalues the neighborhood which the city allowed to build homes up to plant. Local and state officials ignore my complaints. Plant official went out and measured noise with Decibel A meter which doesn't measure low tones put off by motors, pumps and fans. Have so far ignored my request for Octave band frequency analysis. Across town in Cape Coral a similar plant had a 8 foot tall concrete wall built around it for aesthetics. People around SW Cape Coral water and sewer plant would appreciate some aesthetics in the form of at least an eight foot. Maybe it would block some of the noise and smell. Seems like disparate treatment denying /ignoring request to build wall around SW plant. Do your due diligence and caveat emptor.

Robert Pott, Cape Coral Fl
March 1, 2015 5:33am

I heard it for 3 years starting in 2010. I live in a major New England city about a half mile from the ocean. I thought it was construction far off in the distance, boats, or an idling truck somewhere. Drove me nuts for 3 years, and no one believed me. No one else could hear it, and it only happened at night. When I moved in 2012 about 15 miles inland, into a more congested city, it stopped.

Steve, Boston
March 12, 2015 9:04am

Moved to a nice quiet neighborhood summer of 2013. Noticed right away a hum, sometimes I describe it as the Eraserhead hum. Noticed inside house, at all times, sometimes in vehicle while parking in garage, vaguely outside at times. Most annoying when it is quite and still it is not quite due to the hum at bedtime. Well insulated house with dual pane windows throughout. Tried to isolate every system water, plumbing, electric gas. Hum not noticeable in attic. No fans or pumps found. No whirling attic vents. Slab foundation. One other known complaint in the neighborhood from a longtime resident who states that he noticed the hum starting in summer of 2013 (coincides with ground water pumping mentioned below.) No other longtime neighbors I have asked notice the hum. Many neighbors sleep with windows open and I suspect others are annoyed and a way to limit the annoyance is to let in ambient noise (including freeway roar) in as a canceling effect. The hum is persistent almost 24/7/365 with cessations only occasionally for perhaps a day or 2 at a time. Suspect the hum is from individual nearby mechanical sources or combined sources. The possible known sources are (1.) gas utility company pressurizing regional underground natural gas with several massive diesel engines, (2.) a sewage and water reclamation plant, (3) recent additional ground water pumping from public and private water wells located in foothills due to severe drought conditions.

Ray, Goleta, Ca
March 19, 2015 9:33pm

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