Last night at about 1am, at the intersection of 57 East and Madison Avenue in Manhattan—a populated area about four blocks from Columbus Circle—the NYPD used a Long Range Acoustic Device (LRAD) to disperse about 100 protesters who were on the streets.

Footage captured by YouTube user James C shows the weapon in use beginning at the 1:58 mark. Protesters scattered in response to the sound, and either a live officer over a PA system or an automated voice intermittently told protesters between sound blasts that they could not interfere with “vehicular traffic” without risking arrest. The LRAD is deployed multiple times throughout the 5:00 minute video clip.

Shay Horse, an independent photojournalist who was on the scene, posted on the internet that “The NYPD began using it after glass bottles were thrown at them when they made several violent arrests when a march tried to cross Madison Ave.”

One person who was present at the scene, Moth Dust, a photographer, said people became aggravated after the LRAD was used and began throwing trash and rocks in the direction of police. She said she was affected by the sound waves.

“I thought I was fine until I realized I was getting dizzy and migraine was spreading to all over my face,” she said.

LRADs were used in the first days of unrest in Ferguson Missouri, and have been used by police at protests throughout the world. They were developed by the US military after an insurgent attack on the US.S. Cole in Yemen in 2000, and were used by the NYPD against Occupy Wall Street protesters.

According to Radio Free Europe Radio Liberty,

"The LRAD can reach decibel levels as high as 162. For comparison, a normal conversation is usually 60 decibels, while a lawn mower can reach to 90 decibels. A level of 130 decibels is typically considered the average pain threshold for most humans.”

Furthermore, Informed Health Online notes that a jet engine registers at about 140 decibels. Anything at or above this range, IHO explains, “is called acoustic trauma. Depending on how long the ears are exposed to the sound and how intense it is, it may damage the eardrum, the middle ear and/or the inner ear. Damage like this is usually temporary, but some hearing loss may remain.”

The head investor and media relations for the LRAD Corporation in San Diego, California, told Radio Free Europe Radio Liberty that the weapon is so precise that those “standing behind or next to” the device can hardly hear it. However, the YouTube footage shows dozens of people scurrying away from the sound blasts, which can be heard clearly on film.

No coverage of the LRAD use was reported in the mainstream media. Earlier in the night, around 11 PM, CNN correspondent Brooke Baldwin praised the behavior of protesters and the NYPD's response to the protests, remarking on live television, “This is exactly how it's supposed to be.”

Noel Leader, a former 20 year sergeant of the NYPD and co-founder of 100 Blacks in Law Enforcement Who Care, was incredulous about the possibility that an LRAD had been used.

"I haven't heard anything about that,” he told AlterNet. “I'd be surprised if that was the case, because most of the protesters have been nonviolent and peaceful, even though they have been disruptive.

In total, police arrested 219 people at the protests last night, according to Capital New York.