https://mic.com/articles/91091/a-mys...and-nobody-knows-what-s-causing-it#.OddkhWDw7
I'm trying to sleep and this sound is exactly as described. Inside it's louder than outside. It has a perceived direction, sort of. At times, it feels like the inside of your ear is vibrating even if you wear ear protectors. So, it's not just me. Elderly Mom hears it too.
I read the article and accept everything in it. During the last 5 years I read many articles and researches about this subject, I also did my own simple researches.
There are many sources for the VLF that sound like a lorry running outside your house. They are real and hard to detect because they can be very far. It is also hard to detect the direction.
People that can hear VLF can hear it up to 100 times louder than people who aren't sensitive to VLF. This means that there are sounds that only one in 20 people can hear. Once a person is tuned to the sound he can hear it loudly and clearly, people that hear the sound at very low levels can ignore it completely.
Most homes now have double glazed windows and good thermal insulation inside the walls. These block high frequencies but let through VLF. At home you get VLF without the high frequencies noise that destruct your attention from it.
Human brain adjusts its sensitivity to the sounds around. When you are at your quiet home the sensitivity is turned high by your brain and you hear the hum better.
Many people at middle age hear low frequencies better and high frequencies lower.
When you tell your friends or neighbors that you hear a sound that they don't hear they label you as crazy because they are scared of the idea that there is something around them that they can't sense.
I don't hear a hum for the last 3 months but I heard a hum for 3 years before that. The hum affects me in the worst possible way, it turns me angry and violent, it is known side effect. The reason I don't hear a hum now is only because I moved to live in an area that there is no hum.
My first experience with hum started 6 months after moving to my new semi-detached house in Northampton. The neighbor didn't want a foreigner living next door to her so with the help of her friends and family they decided to use noise to drive me away. It started with loud TV and early morning banging on the wall. After 6 months they also learned that the sound from their fan heater attached to the party wall disturbs me. They brought another fan heater to the house and put the two fans running without heat for 18 months 24 hours a day until I sold the house. The old woman who lived there was deaf. Her sons who didn't live there did all the tricks.
3 months after the hum started I moved to live in the garage because the noise was too hard to take. During this time I studied the subject of VLF for the purpose of trying to defend myself. The noise inside my house sounded like a lorry running outside and the highest amplitude was at 35Hz.
From Northampton I moved to France to a house in the country. There was a very similar hum there. It took me several months to find out that the hum source was a quarry 2 miles away that had a saw that stops only every 100 hours or so to load a new piece of granite. I met 2 locals that can hear the hum but they were ignored because most people don't hear it.
Now I live in Nottingham for 3 months and I don't hear any hum.
My advice to you is to go and stay for a few days in another place in another town for a few days and if the hum stops that is likely because there is a hum in your area. You may be lucky and find the source of the noise but you have to be more than lucky to be able to stop it. It is likely that you will have to move to a place that has no hum.