This depends on a lot of factors like distance, direction, and original intensity. But it can be painful or worse, cause permanent hearing loss.

Source: https://www.acentech.com/resources/long-range-acoustic-devices-lrad-and-public-safety/

All good info. A bit outside of this post context but helpful nonetheless.

Good advice but the respirator doesn’t wrap around the ears so in the context of acoustic protection/reflection it doesn’t seem effective. I agree that a shield is conspicuous… I’m just spitballing about total effectiveness in theory. I like the end of the video shared above where the concave parabolic shape of the shield (when reversed) was used to redirect the LRAD sound at the operator. Pretty cool seeing a vulnerability in a system exploited in that way.

Thanks for sharing this video! It’s a great resource. $5 shop headphones and a polycarbonate shield you can make for under $100 beats a $20,000-$100,000 LRAD. I wonder if ear plugs, shop headphones, and a shield would be any more effective.