Upper hearing frequencies/Teenagers
Some public places such as shopping malls have devices that emit noise in the upper frequencies which are less audible to adults - to stop teenagers congregating. Same idea as those rodent repellent devices. My local shopping centre pipes the output of a middle-of-the road music radio station at times through the PA system - which I presume is for the same reason
Could it be that your neighbour wants you to move ?
Biting the hand that feeds IT
