Wristwatch Spares

What could this noise? Subtle, acute / ears ringing as from a single piece of the house.?

Four family members age Miscellaneous hear sound in one room. My son can not sleep in her room where noise is heard. We have checked all the electrical appliances and toys, windows (thought it might be crickets and is not), TV, lava lamp, smoke detector, etc. You can not hear the noise in his closet or hallway or any other room in the house. We even took his watch from the room. It is a constant, barely audible, high pitched sound, as if your ears are ringing and the sound is not real, but you have an eye / headaches, and if in his room for more than a few minutes. What else could it be??? What should we check? He sleeps in the guest room at the moment, because it is unbearable. Myself and our 30-husband to hear, and my son who is 10 and our daughter who is 6. This is not a joke or a riddle ….. Please then only offer thoughtful suggestions. Thank you!

It seems so strange to me. You have checked the capture of the light? And all points who are in the room? Also, have you turned off all the house lights and other electronics while listening to this? My thoughts it is cables or something else. Also, if you have access to the attic, you go upstairs to see if it's something directly above his room making noise? Does it have a clock in the room? It seems that if you've checked everything I can think of.