Ambient Ultrasonics: Sounds Not Everyone Can Hear

[Mister Obvious]

https://www.livescience.com/62533-ultras...nitus.html

[Mister Obvious]

I have a fair bit of experience with being able to hear shit other people can’t.

[Mister Obvious]

https://www.yahoo.com/lifestyle/try-it-c...54778.html

This article talks about some major retailers having an ultrasonic “young people repellant” to keep youths from congregating outside. I’ve heard these at a couple stores over the years and figured they must be to keep animals away or something.