24 Wonder How Long Before This Reaches Police And Military Use (archive.is) posted 3 years ago by Ahaus667 3 years ago by Ahaus667 +24 / -0 12 comments share 12 comments share save hide report block hide replies
It takes an enormous amount of energy to cancel sound waves over even a small area, so it's obviously something much less exciting.
In this case, it's just an IR flashlight that acts as a long-range remote, blinking common versions of mute. More info here.
So basically the same thing that people use in gyms/airports to turn off CNN?