Oakland encountered a variety of non-lethal and less than lethal weapons when hundreds of police… Oakland encountered a variety of non-lethal and less than lethal weapons when hundreds of police officers tried to disperse crowds in Schenley Plaza and the surrounding areas Thursday and Friday.

Police used an LRAD, or Long Range Acoustic Device, to play pre-recorded messages warning people that their gatherings were unlawful assemblies.

When people didn’t move, the police used the LRAD to emit a piercing sound louder than several police sirens combined.

It was the first time the device had been used in the United States.

Pitt police Chief Tim Delaney said he thought the device worked well because it ensured that everyone who gathered in or near Schenley Plaza Thursday and Friday heard the message to disperse.

“I’d like to get one,” he said.

The American Technology Corporation, the company that produces LRADs, says on its website that the devices can emit sound of up to 140 or 151 decibels, depending on the model. That’s about equivalent to the sound generated by a jet engine, according to the American Speech-Language Hearing Association, which also predicts on its website that sound levels become potentially dangerous around 80 decibels.

Elizabeth Pittinger, executive director of the Citizen Police Review Board, said the military is declassifying the LRAD and other weapons for domestic crowd control use.

“We’re moving into a different generation of crowd control by domestic police,” Pittinger said.

Police also used smoke and OC vapor gas, not tear gas, to try to disperse the crowd.

OC vapor gas, Delaney said, is essentially the same as pepper spray or mace. It’s meant to “take the aggression out” of someone, though it can sometimes backfire and make people on drugs become more violent.

“You gotta do it right,” Delaney said.

Assistant News Editor Lindsay Carroll contributed to this report.