Check out "parametric speakers". Amazon has an assembled kit for sale: http://amzn.to/2AxtPBS http://amzn.to/2AxtPBS Also, more info from soundlazer.com, her

Check out "parametric speakers". Amazon has an assembled kit for sale: http://amzn.to/2AxtPBS http://amzn.to/2AxtPBS Also, more info from soundlazer.com, here: http://www.soundlazer.com/what-is-a-parametric-speaker/ http://www.soundlazer.com/what-is-a-parametric-speaker/ Also, reminds me of the MacGyver (original) episode "Soft Touch"- where a Columbian drug cartel tortures a federal agent in a garage using high-decibel noise.