LRAD: Long Range Accoustical Device

I was a little too generous in my previous post when I said we don’t know harm this device causes. From a 2012 NYPD briefing on the LRAD (Long Range Acoustical Device), also known as a sound cannon, via the Gothamist.

In addition to having “loudspeaker” capabilities, the device can also be used, in a special mode, to propel piercing sound at higher levels (as measured in decibels) than are considered safe to human ears. In this dangerous range (above 120 decibels), the device can cause damage to someone’s hearing and may be painful. It is this technology that device was designed for a USS Cole attack-type scenario. … The device could be used to send out sound at a dangerously high level causing attackers to turn away, or at least, to cause pain/hearing damage to try and repel
the attack.

The LRAD devices … were deployed during the RNC in 2004, for use as loudspeakers…. The device was used as a louspeaker to make announcements to the crowd of protesters, with mixed results. No injuries were sustained.

Again from the Gothamist:

While there might be situations where police have a legitimate use for the device, such as dispersing a large and violent group, [Alex Vitale] says this wasn’t such a situation. “LRADs should be used to avoid having to do a baton charge,” Vitale says. “This was used to scatter already scattered protesters.”

And these devices were tested by the NYPD, in an empty parking lot.

Also (and correct me if I’m wrong) the decibel scale is logarithmic: going from 1 to 10 is a ten-fold increase while going from 1 to 20 is a 100-fold increase. But this is the amount of power or energy in sound, which goes up 10 times every time decibels go up 10 units. But the volume of this sound, the way sound is perceived by the human ear, roughly doubles for every 10 decibel increase. 120 decibels sounds twice as loud as 110 dB (as does 110 compared to 100 dB). So 120 decibels sounds something like 64-times as loud as 60 dB, which is volume of normal speech.

In Test #1, spoken voice commands were given. 20 feet away, sound was measured at 102 dB. In Test #2, noise burst were used, and sound was measured at 110 dB. Now 320 feet is a pretty long distance. It’s the length of a football field. Or half the length of an NYC subway platform (yes, the NYC subway trains really are 600+ feet long). The NYPD LRAD tests were done on cold windy winter day at the beach in The Bronx. Sixth Avenue in Manhattan, an urban canyon with hard sides, is less than 100-feet wide (including sidewalks). You can’t get more than 40 or 50 feet from the center of the street. So… what were the results of the NYPD test at a  distance of 50 feet? “Potential danger area. Not tested.” In fact, nothing closer than 320 feet was tested. It might be dangerous.

This is a lawsuit waiting to happen. But the NYPD won’t have to foot the bill. It’s going to be paid for by me and other resident taxpayers.

(Link to the sound cannon and its first use in 2009 in Pittsburgh. And about the military purpose and history of this potential weapon.)