US court confirms danger posed by 'sound cannons'
https://phys.org/news/2018-06-court-danger-posed-cannons.html
Six protesters filed a complaint, saying they suffered from migraines, vertigo, sinus pain and hearing problems as a result of the incident.
"The problem posed by protesters in the street did not justify the use of force, much less force capable of causing serious injury, such as hearing loss," the court said in its ruling.