What are sonic attacks? 21 American Embassy employees were injured in Cuba, with symptoms including dizziness, hearing loss, and headaches. Officials aren’t blaming anyone yet, but they suspect U.S. diplomats were targeted with sonic weapons using infrasound, which are low-frequency sound waves that the human ear can’t hear. The sound waves can penetrate walls so it could have been deployed inside or outside of the Embassy and other sites. Long-range acoustic devices have been used by police and military to incapacitate targets. It’s even used by some cruise ships to repel pirates. They’re easy to deploy and hard to detect.