I live in North Sweden (Skellefteå). I've started noticing the hum and having more and fewer problems with it, depending on house, season and weather, for about nine years.
It got a little better when I moved 20km to the city. (From the third floor to the first floor), and I've heard it at one of two places I have worked at, and also at some friends’ houses.
First, I thought it was a new wind turbine 6km away, but I could sleep very well both this year and two years ago at my uncle’s house, which has nine wind turbines just 1-3km away.
When I have problems, I mostly have it a few days in a row and maxing out after 4 a.m., when it then wakes me. Perhaps there is more than one frequency. Right now, it’s like a sweeping pulse every three seconds, where I can feel the air pressure going up and down.
Sometimes it’s like a fan spinning faster and faster, up to 10hz or something, but the speed is randomly accelerating/decelerating (perhaps sometimes also constant, but I'm not sure, just as if it were a fan).
Another reason why I think the sound has many frequencies is that the room I am in seems to define where I feel it. In my computer room, I feel it a little more in my head, and in the living room I feel it more in my chest and stomach. Sometimes it feels like my eyeballs are vibrating.
I actually moved from my last apartment and to the city because of the problem. It was so severe that I had to try to sleep on the floor on the bathroom, which almost had no sound, but then in the night, the frequency had changed to it was also in there, but could then be better in another room. The toilet was at the end of a long hallway, so I think that is why it sometimes resonated on a very low frequency. It felt like a big hammer on my heart and internal organs.
I called someone to check for infrasound. They measured at daytime, and they said that their instrument did not measure below 20 or 30hz because its not possible to legally complain about lower frequencies than that. After measuring for five minutes, he said there was no noise, although he said that he could see the noise curve starting to increase the closer to 30hz it came, so he said it could be some kind of overtones and he could see a lower frequency noise, but he never left it to measure during the night either.
I found I was EMF sensitive around the same time I discovered I can hear this hum, and I also had an infection in my right ear and got tinnitus, hair loss and depression. My EMF sensitivity started with me feeling tired with working with computer monitors all day and all night, and then I also noticed I felt depressed when within one or two meters of fluorescent light. It felt like my eyebrows went down.
It takes me a few minutes before getting depressed when I am subjected to microwaves. I now have two field meters and I’m sensitive to around 1-25microwatt/m2, but I don’t want to bore you with that, but I also heard that many EMF sensitive people also are infrasound sensitive.
However, the times when I felt extra EMF sensitive I have have not had more problems with the hum. Perhaps the EMF is more coupled to how strong my nervous system is, and the hum sensitivity more dependent on season and temperature outside, etc.
Perhaps some foods increase sensitivity too, like nuts and lack of sleep and water, and too much or too little exercise.
Since I quit a stressful job two years ago, my depression has been gone. My EMF sensitivity is better too, and perhaps also my infrasound sensitivity.
But now all of a sudden, I can’t sleep for a few days except at daytime like some other person said. It helps to move to another room. Sleeping near my apartment door/lobby works best. I can’t hear the sound outside, I don’t think, but I could at my old house 20km away.
There I noticed that when I walked at a place where the road went very strongly downhill, the sound disappeared. It came back when I walked back to the top of the "hill/road" again.
Apart from the room acoustics/resonances making a difference, I also notice that that hum noise differs a little depending on how I place my doors. Big doors have the most impact, but I also can feel a little difference if I open all cabinet doors in my kitchen or closet. At some angles, they seem to dampen the noise a little or change the harmonics as if I were inside a flute.
I’ve noticed that when the infrasound hum is at its peak, I sometimes can see and feel my doors swaying a bit as if they were circulating in a wind draft going forward and backward.
I wish I could come up with something that could measure it. My uncle, who is an inventor, suggested a pen laser mounted on a door, but I’m not that practical.
I could also mention that arranging furniture in my house also made some difference, and having a round pallet for sitting on in the room helped too, but then again it could obviously not help enough. This apartment building is said to be have natural ventilation, i.e., no fans, but it does have a large chimney.
My last apartment with more problems was a few km from a big industry melting gold and the harbor, etc. There might be some super small bioconverting plant a kilometer or so from this house.
I can hear humming from the large bioconverting plant in my city from about 2.5km across the river and I can almost see the chimney from that range). But I live 6km from it.
I hope this can be of help to someone. Perhaps someone could make a web database of cities where the hum has been heard. I would myself. I know one does not exist. – Anders, Sweden. Going to try to sleep now. It’s 8 a.m.