The New Scientist and others are running a story about a technique that seems to be able to silence a braying racist mob:

Soccer hooligans could be silenced by a new sound system that neutralises chanting with a carefully timed echo.

Stadiums could use the technique to defuse abusive or racist chants, say the Dutch researchers behind it. The echoes trip up efforts to synchronise a chant, neutralising an unwelcome message without drowning out the overall roar of a crowd.

Cool! How long before it’s used on peaceful protesters?