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A long-range acoustic device (LRAD), acoustic hailing device (AHD) or sound cannon is a specialized loudspeaker that produces sound at high power for communicating at a distance. It has been used as a method of crowd control , which has caused permanent hearing damage , having an extremely high decibel capacity (up to 160 dB measured at one ...
Sonar (sound navigation and ranging or sonic navigation and ranging) [2] is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances , communicate with or detect objects on or under the surface of the water, such as other vessels.
A long-range acoustic device produces a 30 degree cone of audible sound in frequencies within the human hearing spectrum (20 - 20000 Hz). An LRAD was used by the crew of the cruise ship Seabourn Spirit in 2005 to deter pirates who chased and attacked the ship. [ 3 ]
SURTASS LFA is a long-range, all-weather, sonar system with both passive and active components, operating in the low frequency (LF) band (100–500 hertz [Hz]). USNS Impeccable has the original LFA system, weighing 155 tonnes; the 64-tonne Compact LFA derivative was developed for the smaller Victorious class.
The original system was capable of oceanic surveillance with the long ranges made possible by exploiting the deep sound channel, or SOFAR channel. An indication of ranges is the first detection, recognition and reporting of a Soviet nuclear submarine coming into the Atlantic through the Greenland-Iceland-United Kingdom (GIUK) gap by an array ...
In response to Deep Sea Vision’s potential find, Nauticos said long-range sonar images have historically proven to be deceiving, especially in areas with geological formations.
SoundSleep White Noise Sound Machine. Homedics has long been a favorite brand of ours for its affordable, niche home products, including everything from foot massagers to portable humidifiers.The ...
Transmission loss (TL) is proportional to range, (the farther the sound travels the more the loss), and to sound frequency. In monostatic sonar the sound first travels from projector to target, then the same way back from target to receiver, so two-way loss is just 2TL, where TL is one-way loss. In bistatic sonar the total loss (in decibels) is ...