"Sonic attack" may have been two ultrasonic signals accidentally interfering
> Yan was even able to embed an ultrasonic version of the Rick Astley song “Never Gonna Give You Up,” which became audible at the point where the two signals crossed.<p>At 33C3 I rode an escalator when I suddenly heard "Never Gonna Give You Up" but apparently no one else did. It was over after a few seconds. At the top of escalator there was a guy pointing a directional speaker at random people.<p>Only reference I could find is in German, but it has a picture [1].
The story says the guy on the picture is not the inventor of the device.<p>EDIT: The thing is a parametric ultrasonic speaker and the design files and software are on GitHub [2].<p>[1] <a href="https://motherboard.vice.com/de/article/784z74/33c3--hacker-zeigen-ihre-gadgets" rel="nofollow">https://motherboard.vice.com/de/article/784z74/33c3--hacker-...</a><p>[2] <a href="https://github.com/niklasfauth/parametricspeaker" rel="nofollow">https://github.com/niklasfauth/parametricspeaker</a>