The Hum

McPherson, 2015

It creeps in slowly in the dark of night, and once inside, it almost never goes away.  It’s known as the Hum, a steady, droning sound that’s heard in places as disparate as Taos, New Mexico; Bristol, England; Kokomo, Indiana; Auckland, New Zealand; Largs, Scotland and, as it turns out, many other places. While reports of “unidentified humming sounds” pop up in scientific literature dating back to the 1830s, Lallanilla (2013)  reports references to the Hum started trickling in during the 1950s from people who had never heard anything unusual before.  These people were suddenly bedeviled by an annoying, low-frequency humming, throbbing, or rumbling sound.  Is it gravity, ocean waves, tectonic plates, faint earth tremors, TV or cellphone towers, tinnitus, aliens, electronic fields, a secret military base, or just someone’s truck running outside?  What IS this thing called the Hum? 

The Hum

Click Here for a Video on The Hum

Lander (2014) describes the Hum as a generic name for a series of phenomena involving a persistent and invasive low-frequency humming noise. Hums have been reported in various geographical locations. It seems to be heard more in rural than urban areas, probably because noise levels in urban areas cover up the hum sound in crowded parts of the world. Difficult to detect with microphones, the Hum is most often described as sounding similar to a distant idling diesel engine and its source and nature are difficult to hum1localize.  Leventhall (2003) reports that the Hum is generally heard by only 2% of the population in the areas where it seems to prevail and mostly by those 55-77 years of age. A firsthand description of the sound by a person that hears it is, “The “droning engine” descriptions fits it pretty well. It sounds like a very distant idling vehicle, but there is also a vibratory aspect to it….but muffled by distance and walls. Also like when you can hear/feel the bass from stereo systems in other people’s cars.”  Another person’s description of  the Hum:   “Very low frequency Diesel engine – like throbbing sound. Sometimes it drones on for long stretches before it has a short pause / throb, then picks up again, repeating the rhythm.

McPherson, 2015
McPherson, 2015

Sometimes the droning / throb rhythm speeds up slightly and other times it has irregular quick throbs, similar to irregular heart beats. I can’t block it out even when plugging ears; therefore it appears to be sensed by the body, which interprets it as sound. I only hear it / sense it inside enclosures; in house, parked car in driveway and partially outdoors when under carport, which has ceiling but is open on 2 sides. Its worse between 10 pm and 7am when all other external noises (e.g. traffic) are not or less present.

Areas of the World where the Hum occurs.  McPherson (2015)
Areas of the World where the Hum occurs. McPherson (2015)

 It wakes me up middle of night when loudest between 2am and 3:30am and it’s difficult to get back to sleep, if at all. I have heard it at other places I have visited. Within my very close group of family / acquaintances, which are about 13 people, only 3 can hear it and 1 can only sense it.”  

The personal experiences with the Hum seem to have several factors in common:

  • Generally, it is only heard indoors and is louder at night than during the day.
  • It is more common in rural or suburban environments.
  • Modern manifestations of the contemporary hum have been widely reported by national media in the United Kingdom, the United States and Australia since the early 1970s. 
  • While there is substantial debate it does not appear to have an acoustic basis.
  • The map (McPherson, 2015) presents the areas where the Hum is heard around the world. 

What Causes The Hum?

   While there have been a few investigations into the origins of the sound, its analysis has been extremely difficult and it has become a mystery.  In 2006, New Zealand scientists Dr. Tom Moir  and Dr. Fakhrul Alam felt that they had captured a recording of hum3the mysterious hum that had been heard in and around the city of Auckland. They made a recording and dubbed the sound an unidentified acoustic phenomena.  In 2006, Moir and Alam pinpointed the low-level drone at a frequency of 56Hz, which is very close to the 50Hz frequency produced by the 240 volt AC main electricity supply delivered to homes in New Zealand (and Australia).  Although 56Hz is within the standard range of human hearing (20-20,000 Hz.), it is too low for many people to pick up. 

Play Moir’s Sample Recording- Its very low frequency and you may not be able to hear it…..

After review the research to date on the Hum, Dunning (2008) summarized the phenomena as follows:

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. Therehum3 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 hum6that 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.”

Dunnings’ comments notwithstanding, there is still research on the Hum going on routinely.  Dr. Glen McPherson, a lecturer at the University of British Columbia first noticed the Hum in spring of 2012.  Later, he discovered the Hum community and sensed a need for a unified, moderated, and serious place for discussions and research surrounding the Hum. This led to the World Hum Database and Mapping Project According to McPherson the World Hum Database and Mapping project is a place for disciplined inquiry, and not for wild speculation and conspiracy. In his opinion,  there are many entertaining and interesting websites available for those who want to indulge in those activities. Thus, despite the “Nay Sayers”,  McPherson and many others around the world continue to research the Hum.  Maybe one day the mystery will be solved.

hum7SO What Did We Learn about the Hum?

Unfortunately, not too much.   In the beginning we asked, is it gravity, ocean waves, tectonic plates, faint earth tremors, TV or cellphone towers, tinnitus, aliens, electronic fields, a secret base, or just someone’s truck running outside?….just what IS this thing called “the Hum? At Hearing International, today’s conclusion is as follows:

While there are data and recordings that seem to show the Hum could be acoustical and other research that presents alternative scientific explanations, as with all research, there are good studies and not so good studies.  For the moment, however, it could just as easily be someone’s truck running outside or a group of individuals with a spastic tensor tympani muscle.




Dunning, B., (2008).  Can you hear the hum?  Skeptoid.  Retrieved June 3, 2015:

Lallanilla, M. (2013).  Mysterious hum driving people crazy around the world. Livescience.  Retrieved June 2, 2015:

Lander, K. (2014) We explore the phenomena known as the the hum.  Supernatural Magazine.  Retrieved June 2, 2015:

Leventhall, G., (2003). Acoustic consultants report 2003.  Livescience.  Retrieved June 2, 2003:

McPherson, G., (2015).  World Hum database and mapping project.  Retrieved June 3, 2015:

Tasker, J. (2014). Quest Atearoa.  Lulu Enterprises.  Retrieved June 3, 2015:,+a+computer+engineer+at+Massey+University%27s+Institute+of+Information+and+Mathematical+Sciences,&source=bl&ots=SJZoHofn-P&sig=2Qy5dv7yETNspB6wGYCEE60enKA&hl=en&sa=X&ei=tOJuVa_yIMrBtQWk5YKgDg&ved=0CC0Q6AEwAg#v=onepage&q=Tom%20Moir%2C%20a%20computer%20engineer%20at%20Massey%20University’s%20Institute%20of%20Information%20and%20Mathematical%20Sciences%2C&f=false


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About Robert Traynor

Robert M. Traynor is a board certified audiologist with 45 years of clinical practice in audiology. He is a hearing industry consultant, trainer, professor, conference speaker, practice manager, and author. He has 45 years experience teaching courses and training clinicians within the field of audiology with specific emphasis in hearing and tinnitus rehabilitation. Currently, he is an adjunct professor in various university audiology programs.