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Bullets, missiles and swords may be what most people think of when it comes to weapons, but sound has also been deployed over the millennia to disrupt, confuse or even injure opponents on the global battlefield.

From the Israelite army of trumpet-blaring priests who shook the walls of Jericho 3,500 years ago to the U.S. Navy’s current use of long-range acoustic devices, nations and their armies have deployed both sonic weapons and various sounds as a form of attack.

“All through history the use of sound has been used to threaten the enemy and raise the morale of your own people,” says Herb Friedman, a retired sergeant major in the U.S. Army’s psychological operations program.

Most sound has been weaponized to disorient or anger opponents. In World War II, during the German siege of the Soviet city of Stalingrad in 1942, Soviet troops kept German forces awake at night by playing Argentine tangos through loudspeakers. In Vietnam, U.S. forces turned sound into psychological warfare.

“We played music, we played insults, we played the sound of tanks and tigers,” Friedman says, adding that U.S. forces even played Doris Day songs over loudspeakers on the front lines. “It seemed to affect them,” he says.

In 1989, during the U.S. invasion of Panama, U.S. troops blasted heavy metal (plus The Doors and The Clash) at Panama’s leader Manuel Noriega, who had barricaded himself in the Vatican's Panama City embassy. He surrendered.

That seemed to give FBI agents an idea. During the 1993 siege of the Branch Davidian cult complex in Waco, Texas, agents tried to get David Koresh and his followers to surrender by playing all kinds of kooky songs, from Nancy Sinatra’s “These Boots Were Made for Walkin’ to Christmas carols and Tibetan chants. That psy-ops effort failed, and after a 51-day standoff, Koresh and 75 of his followers died in a fire that engulfed the complex.

During the war in Iraq in 2004, U.S. Army forces in Fallujah used Humvees mounted with loudspeakers to hurl Arabic insults (mostly about their families) toward Al-Qaeda forces who had occupied the city.

And also in Iraq, for perhaps the first time, the Pentagon deployed an actual sound weapon known as LRAD, or Long-Range Acoustic Device. Used initially for crowd control, the LRAD was mounted on Humvees and directed toward Iraqis gathering at checkpoints that were often the scene of suicide bombers. The LRAD devices have several settings, and can be used to give instructions at a long distance, or even set to create pulses up to 149 decibels (hearing a jet engine 100 feet away registers 140 dB in comparison).

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A Los Angeles County Sheriffs deputy in riot gear stands ready to use a sound cannon, or Long Range Acoustic Device (LRAD), against protesters near a campaign rally by presumptive GOP presidential candidate Donald Trump at the Anaheim Convention Center on May 25, 2016. 

Police units used LRAD devices at an Occupy Wall Street rally in 2011 and in Ferguson, Missouri, in 2014. They are currently deployed on naval ships to deter smaller boats from approaching. More than 20 countries are now using the LRAD. Israeli Defense Forces have used it to break up Palestinian protests, Japanese whaling ships have repelled environmental groups and several cruise ships have used it to fight off pirates in places like the Horn of Africa or Indian Ocean.

Most recently, mysterious incidents in China and Cuba in 2017 and 2018 led some to suspect that sound had been deployed as a weapon against Americans living in those countries. Chinese officials denied in late May 2018 that they had conducted a sonic attack on an American diplomat based in Guangzhou in southern China. The diplomat said he suffered traumatic brain injury after feeling abnormal sounds and pressure in his ears over several months. Some U.S. officials said the incident could be similar to symptoms felt in 2017 by U.S. diplomats in Cuba, who also reported injuries consistent with a sonic attack.

The attacks in Cuba affected nearly two dozen workers with unexplained headaches, dizziness, cognitive issues and sleep loss. The symptoms occurred after the workers reported hearing strange noises. The worst hit were intelligence agents, leading to speculation that it was a directed at them by Cuba’s government. The problem is no weapon is known to cause all the reported symptoms. It may have been the symptoms were caused by a combination of chemical toxins and a low-frequency sound that produce disorders of the inner ear, according to a report in Wired.

“What happened in Cuba doesn’t make any sense," says Toby Heys, leader of the future technologies research center at the Manchester University of Art. Although, Heys adds, it could that some kind of new sonic weapon was at play. Further investigations may determine whether or not the murky incidents in Cuba and China represent new fronts in the weaponization of sound.