Inside the world's quietest room
https://edition.cnn.com/style/article/anechoic-chamber-worlds-quietest-room/index.html
Even if you have never entered the world's quietest room, you may have heard strange sound from floor, wall, or ceiling when sleeping in a comparatively quiet room. It's as if someone is walking on corridor.
Though I don't have a sense of detecting ghost, those who have that sense can identify who the ghost is?
