I thought this was ADS since I can't hear the sound in any of the videos of this protest I've seen, like in this LRAD video and in this LRAD defense video its super loud.

So I don't think headphones would help here since ADS just heats the water in your body but a riot shield would help just on the parts of the body it covers since the ADS can't penetrate very far, not sure if conventional clothing would work or if you would have to cover your body in something like aluminium foil to stop the millimetre waves penetrating skin.