Here, US military is testing it during Vietnam War as a possible weapon. Only problem is: they're using it off a ship, & targeting the sound at coast. Not only are a lot of non-combatants affected, it's also affecting the whales in the ocean.
In fact, much of the story is about attempts to refloat whales that wash ashore as a result of their senses getting confused because of these subvocal sounds.
Fact sheet.First published: Analog, September 2013.
Related: Stories of Alec Nevala-Lee.