Đảm bảo hiện tượng ma ám không phải do sóng hạ âm gây ra. Loại trừ các yếu tố không mang tính siêu nhiên. Đi kiểm tra sức khỏe tâm thần.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
These low frequency hums can cause nausea, feelings of fear and even manifest shadows at the corners of your vision. These are caused by the vibrations of the infrasound, depending on the intensity of the sound wave. French robotics researcher, Vladimir Gavreau, allegedly produced such effects on himself and his fellow researchers through infrasound.  Animals can pick up infrasound in ways that humans can't. Scientists believe that this might be how many animals can sense natural disasters.  Bui