Pepper spray can often be the crowd control method of choice for police departments because it easily subdues subjects without permanent damage. But that's not all police are using to help control "Occupy" protests around the country.
You may not think sound can be a powerful weapon, but sound tactics can be effective at dispersing crowds. Gizmodo has more on the Long Range Acoustical Devices (LRADs) that can be used as both messaging devices and crowd deterrents:
The device produces a sound that can be directed in a beam up to 30-degree wide, and the military-grade LRAD 2000X can transmit voice commands at up to 162dB up to 5.5 miles away.
The LRAD corporation says that anyone within a 100 meters of the device's sound path will experience extreme pain. The version generally utilized by police department (the LRAD 500X) is designed to communicate at up to 2000 meters during ideal conditions. In a typical outdoor environment, the device can be heard for 650 meters. The 500x is also capable of short bursts of directed sound that cause severe headaches in anyone within a 300-meter range. Anyone within 15 meters of the device's audio path can experience permanent hearing loss. LRAD claims the device is not a weapon, but a "directed-sound communication device."
The LRAD device has been used on several occasions against activists in the US. The first documented use was in Pittsburgh during the G20 summit in 2009. The Pittsburgh police used it again following the Superbowl in 2011. The LRAD has reportedly been used against Occupy protestors in Oakland and recently against Occupy Wall Street protestors in Zuccotti Park.
The New York Daily News reports the police as denying use LRADs as "sound cannons" but as effective means to spread messages to the crowd:
“We don’t use it to disrupt. We don’t use it as some horrible noisemaker,” said Police Department spokesman Paul Browne.
“We set it up away from where a crowd is. We create a 50-foot safety zone. It sends out a clear, uniform message that can be heard for several blocks.”
Reported side effects, according to Gizmodo, have included permanent hearing loss, making use of LRADs a controversial tactic:
Permanent hearing loss begins at 130dB, and if the device is turned up to 140dB, anyone within its path would not only suffer hearing loss, they could potentially lose their balance and be unable to move out of the path of the audio. The device is also entirely operator dependent, which could lead to serious ramifications if the officer in charge doesn't have sufficient training.
The Vice President of Business Development for the LRAD Corporation Scott Stuckey didn't explicitly come and tell the New York Daily News the devices can be used as weapons. The company's website states use of the speakers for humans as delivering a loud clear message :
“Can your car horn be used as a weapon? Can you play loud noise with the LRAD? Absolutely,” said Stuckey. “They could cover their ears if it’s too loud.”
Here is an example of when an LRAD was used to break up a protest in Pittsburgh in 2009:
LRADs were even used against a team on Animal Planet's Whale Wars that was attempting to protect whales from poachers:
The device was first developed in the early 2000s so naval ships could easily communicate with one another. The company's website also notes the device being used to deter birds away from wind farms, airports and runways, and even farms.