It's possible this could be fought by building a fairly large
   corner-cube retroreflector and aiming it at the source of the sound.
   While that might not be precise, it would send a lot of sound back to
   the area around the emitter.
                              Jim Bell
   [1]https://www.thedailybeast.com/how-the-lrad-went-from-a-pirate-deterr
   ent-to-a-police-crowd-control-tool

References

   1. https://www.thedailybeast.com/how-the-lrad-went-from-a-pirate-deterrent-to-a-police-crowd-control-tool