Several techniques tested for neutralizing the effects of Long-Range Acoustic Device (LRAD) like what was used in Serbia. Knowledge is power!
Several techniques tested for neutralizing the effects of Long-Range Acoustic Device (LRAD) like what was used in Serbia. Knowledge is power!
That last one sound the least plausible, but most karmically appropriate tactic.
But basically tldw is: Earplugs or better passive hearing protection.
Sound has to cross all of the mediums they propagate through. At every change in medium, some sound will reflect. The reflection is greater the bigger the difference in mass and/or stiffness.
For regular, spherical spread sound a lot of it spreads widely and laps around edges (like waves around a pier, a bit flanks around). For narrowed/concentrated waveforms, this is lessened.
Thus a barrier stiffer and/or heavier than air does make a difference, about 3 dB per doubling of mass and/or stiffness, a riot shield will probably give you about 10 dB.
The effect is higher if you do a double barrier with air in between. A two-pane window can easily do 20 dB. Probably the same with a two-pane riot shield.