Use as repellent

We all know that the sound can be very uncomfortable and that it's permanent distribution can be bothering. With regard to technological feasibility, we can broadcast uncomfortable directional sound signal to particular locations to draw back animals or persons.

Even today we can use the directional sound as an invisible repellent against pigeons at the monuments, or as repellent against homeless people from the locations they are associating and harassing. Example for use can be the locations in front of Shopping Mall Anděl in Prague.