As always, a preamble. There are many hums. I refer here to the classic Hum, described in the research literature and reported by Hum sufferers at http://www.thehum.info.
I suspect that the Hum is a biological reaction to the multimode propagation and subsequent interference of VLF electromagnetic energy, compounded in some cases by existing sources of otherwise inaudible low frequency sound and infrasound. It is an activation of the auditory system detectable by a small proportion (less than 5 percent) of the population who are acutely sensitive to the presence of low frequency sounds or who have specific anatomical conditions. Increasing numbers of increasingly powerful VLF transmitters, via ground wave, skywave, and magnetic conjugate propagation modes, create ground interference and standing waves that create locations with intense levels of VLF energy. The odd behaviour of the Hum is caused by diurnal, seasonal, and geomagnetic disturbances affecting the ionosphere.
World Hum Map and Database Project 
Hi Glen
I am new to the world of hum research and I have not yet read all of your entries on this site. So please bear with me if you have covered this already. But to test your hypothesis, why not build a VLF radiation opaque box (a Faraday cage perhaps), jump in, and see if the hum is still there.
I understand the concept of skin depth. I think you mentioned that the foil in tinfoil hats would have to be at least 1 inch thick to be effective in blocking VLF emr. Would that mean that a box made of 1 in. thick Al would work in this regard? Perhaps the necessary skin depth could be achieved with a cheaper material such as steel.
I suppose that you must have thought about something like this before, and that you are either already going to try it, or that for some reason it is an impractical or unrealistic idea. So I was curious as to what you thought.
It has never occurred to me that this ‘sound’ that i was hearing was anything more than just sound. But I have always been intrigued by the the way that it is still there when I block my ears, put my head under a pillow etc. etc. I have often wondered how any sound could ‘penetrate’ that well.
The notion that this ‘sound’, the one I can hear right now in fact, is possibly not sound at all but the product of VLF radiation seems extraordinary to me. Bit of a worry too, I’m not sure that I fancy being a radio receiver, at least not in this way!
Again, apologies if you have covered the notion of VLF – proofing oneself with a radio opaque container before. I’ll go and read the rest of your entries now
cheers
I knew this would happen! The first thing I have just read about was the Denning box experiment. Which kind of makes my above post a bit redundant. I’ll try and do my homework next time!
cheers
Thank you for the primer on VLF. It has helped to understand what may be occurring. I first noticed the hum back in early May. Having never “heard” it before and the experience was unsettling and disturbing, especially to my sleep. Oddly enough it was only on a couple of nights per week. I had been living in the house since November of 2012 and would surely have noticed it if it had been occurring earlier. Since June I have been using a fan at night and that may be masking the hum. I can still hear it at other times of the day, mostly early morning and late afternoons. Only occasionally is it heard outdoors.
I ran across an article on Yahoo several weeks ago and was most surprised to find that others have also experienced this. Even more surprising was listening to some of the recordings which were very similar. It was stranger to find out it had no known source than me being unsuccessful at finding a local cause. The area I live in is close to train tracks and there is an air force base in the area . I was attributing the hum to them. Now I do believe they are the source.
I have read David Demings paper and that was helpful as well. I appreciate you efforts to solve this mystery.
Correction– I do not believe the train tracks are the cause, the air force base, I’m not so sure about.
[…] I made a mistake after I finished cataloguing these for you. My mistake was research. It led me to the Wikipedia entry on “The Hum” which disturbed me greatly. Of course it has its own website. Of course. This led me to one of the greatest paragraphs I have ever read: […]
I’ve heard a hum since November 2013, though I’ve lived in my home since 2008 and never heard it before then. It is a low, deep thrumming sound, pervasive and invasive, which I hear everywhere in my home, and as soon as I drive into the driveway. Neighbors don’t hear it, but a visiting relative did. I was driven to tears and distraction at first. I visited City Hall to ask about other complaints, or any public works that might be the cause, to no avail. I’ve driven around town, and can hear it at certain points. The waste water treatment facility seems to give out a sound that might be it. There is a refinery in town but I don’t hear the noise when I drive there. We’re near a water straight with occasional cargo ships and also near train tracks, but how do I find out what the actual source is? On very rare occasions it stops. I’ve begun a log to see if there is any pattern. Now I constantly have a white noise app playing (as I do now), so I can live and sleep in the home. It is excruciating to live with this day in and day out, and I pray you are able to uncover the source.
I’d like to see a survey of us “Hum hearers” that asks about locale such as proximity to industry, transportation, water, refineries; physical attributes and history such as cranial, inner ear and dental accidents and health; length, duration and frequency of hearing the Hum; demographics, and any other relevant factors that when aggregated might help determine commonalities or anomalies among and between us.
The Hum Database contains a lot of above information you ask about. Feel free to peruse it and suggest other survey questions.
Thanks Glen; I found you database after leaving this comment, and filled out the survey.