LRAD 1000xi Testing: 110' USCG Cutter

May 05, 2017

LRAD 1000xi Testing: 110' USCG Cutter

Long Range Acoustic Hailing Devices, more commonly known as LRAD, enable vessels to hail, notify and warn approaching vessels at significant ranges with clear voice or prerecorded messages in any language.LRAD 1000xi

California based LRAD Corporation is a Global Leader in the production of Long Range Acoustic Hailing Devices. The company provides vessel/platform operators the ability to determine the intent of a potential threat, such as a piracy event, at the earliest possible moment and at the greatest distance.

SeaBourn Spirit
In Novermber 2005, the luxury cruise liner Seabourn Spirit employed LRAD to repel a pirate attack off the coast of Somalia. The pirates did not succeed in boarding the vessel and eventually fled.LRAD 1000xi Testing: 110' USCG Cutter

M/V Resolve:

M/V Resolve used LRAD to Repelled Pirate Attack at 1100 Meters. “aimed her (LRAD) using the sight, went to maximum power and volume and activated. The first time the boat seemed to fall off course momentarily, then come back. I activated the unit a second time, this time holding it for a longer period and “waving” it across the target to make sure I “hit”. The boat instantly went dead in the water and broke off its attack. The range was estimated at .6 to 8 nm. The crew all saw it and they were cheering. I now have a ship full of believers. Lessons learned: It works.”
– Captain M/V Resolve

How Does it Work?

The LRAD's job is to make sound - a lot of sound. It produces extremely loud sound that is audible over relatively long distances. But it's not limited to producing painful noise for use as a weapon system. It can also amplify voices or recordings to a decibe level that is loud and clear but not painful or incapacitating.

Instead of using one big, moving device to make all this sound, the LRAD uses lots of little ones. A speaker usually uses one rapidly moving diaphragm to make sound. The LRAD uses has an array of piezoelectric transducers. A transducer is simply a device that changes one kind of energy into another kind of energy. In this case, it changes electrical impulses into sound.

All of these transducers are attached to a mounting surface. They're staggered to allow more of them to fit into a smaller space. This helps the LRAD create very loud sounds -- identical waves emerge from the transducers, and their amplitudes combine to create louder sounds.

How LRAD works

How Loud is It?

The LRAD 1000xi that was installed on both 110' Cutters has the capability of outputting 153db at 1 meter and highly intelligible voice messages over distances up to 3,000 meters. According to the National Institute on Deafness and Other Communication Disorders, any sound over 90 dB can damage a person's hearing.

                                             

Just to put it in perspective, the maximum output of the LRAD 1000xi is comparable to a military jet take off 100m away. That is loud!!

LRAD 1000xi Testing: 110' USCG Cutter

LRAD 1000xi Testing: 110' USCG Cutter

 


Sources:
Tracy V. Wilson "How LRAD Works" 3 March 2006.
HowStuffWorks.com. <http://science.howstuffworks.com/lrad.htm> 5 May 2017

Mark Lowe " LRAD"  April 12 2012 http://www.marsecreview.com/2012/04/8544/ 5 May 2017