DD was complaining about a noise in her room - couldn't hear it, did nothing. The next day, in evening, she came to me in tears saying cannot stay in her room as the noise was driving her mad. Her Dad had been up earlier & told her there was no noise, & she was desparate as couldn't do homework.
I went in her room & couldn't hear anything. She screams at me - you MUST be able to! So, to humour her go round room carefully pulling & shaking anything moveable.
Then we get to the insect/rodent repeller that is plugged into DD's room (she is nearest the loft access where the were living. It has a rocker switch that has been moved, that turns it into a mozzie repeller. When I move this switch she shouts "It's stopped!". I turn it back on & she immediately covers ears again. DH & I cannot hear it at all.
So- if you want to get rid of any teenagers......