As someone who has suffered from tinnitus for a few years, I empathize with people who live somewhere that is known to have “the hum.” What is the hum? It is a low-frequency humming or droning sound whose source remains unclear.

This phenomenon, or collection of phenomena, has been reported in numerous places in the United States and beyond. The low-frequency humming, or rumbling, or droning noise is not audible to all people, which makes it harder to track down and harder for some people to believe.

These hums are associated with an area and one famous one is the “Taos Hum” in New Mexico. Though it has received quite a bit of attention, only 2% of the population has the ability of hearing it. Of course, that 2% finds it to be not only irritating but mysterious and frustrating.

I have to admit that my first contact with a hum was from watching a 1998 episode of The X-Files titled “Drive.”  Agent Mulder’s theory is that extremely low frequency (ELF) radio waves might explain the Taos Hum.

These “hums” are not the only “unexplained sounds” out there that some people can hear while others can not.

People describe the hum as being comparable to that of a distant diesel engine idling. All of the logical explanations – machinery, household appliances, traffic noise – have been investigated and ruled out. That leaves much room for speculation, fringe science and theories that are psychological to the paranormal. Sure, secret government mind control experiments and underground UFO bases have been listed as possible causes.

Reports of the Taos Hum go back more than 20 years. Researchers at the University of New Mexico set up sensitive equipment in the homes of some of the people who claimed to hear the hum but nothing unusual was detected. Each “hearer” described it as compared to a different frequency between 32 Hz and 80 Hz and similar results have been found in an British study.

Hearers are both male and female, with middle-aged people being more likely to hear it.

Though hearers can move away from the hum and not hear it (so it’s not tinnitus) they can’t block it with earplugs. It is often described as vibrating within their bodies.

There is now a World Hum Database and Mapping Project (and a blog with updates) that started in 2012 to build detailed mappings of hum locations and to provide a database of Hum-related data for professional and independent researchers. I looked on their map and found reports all around my part of the country.