Not to be confused with hydraulophone, a musical instrument.
A hydrophone (Ancient Greek: ὕδωρ + φωνή, lit. 'water + sound') is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates an electric potential when subjected to a pressure change, such as a sound wave.
A hydrophone can detect airborne sounds, but will be insensitive because it is designed to match the acoustic impedance of water, a denser fluid than air. Sound travels 4.3 times faster in water than in air, and a sound wave in water exerts a pressure 60 times that exerted by a wave of the same amplitude in air. Similarly, a standard microphone can be buried in the ground, or immersed in water if it is put in a waterproof container, but will give poor performance due to the similarly bad acoustic impedance match.
A hydrophone (Ancient Greek: ὕδωρ + φωνή, lit. 'water + sound') is a microphone designed to be used underwater for recording or listening to underwater...
Atmospheric Administration (NOAA) using its Equatorial Pacific Ocean autonomous hydrophone array. Upsweep Upsweep, from the NOAA website at 20x the original speed...
terminating at NAVFAC Barbados on 6 July 1962. The linear arrays with hydrophones placed on slopes within the sound channel enabled beamforming processing...
the subsurface water cycle. Using both ocean-bottom seismometers and hydrophones, the scientists are able to map structures as deep as 97 kilometres (318...
water, sonobuoys have both a radio transmitter above the surface and hydrophone sensors underwater. Sonobuoys are ejected from aircraft in canisters and...
towed array sonar is a system of hydrophones towed behind a submarine or a surface ship on a cable. Trailing the hydrophones behind the vessel, on a cable...
was detected by the Equatorial Pacific Ocean autonomous hydrophone array, a system of hydrophones primarily used to monitor undersea seismicity, ice noise...
sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit of sound pressure is the pascal (Pa). A sound wave in a transmission...
sound. The British made early use of underwater listening devices called hydrophones, while the French physicist Paul Langevin, working with a Russian immigrant...
U-boats to find targets, which significantly lessened losses; after the hydrophone and depth charges were introduced, destroyers could potentially successfully...
deep-sea volcanoes can be difficult to detect at great distances using hydrophones.[citation needed] The critical temperature and pressure increase in solutions...
hemisphere, which is primarily ocean. Hydrophone monitoring stations consist of an array of three hydrophones suspended from cables tethered to the ocean...
equipment may be required instead of the usual microphone, such as a hydrophone (for underwater sounds), detectors of ultrasound (very high-frequency...
Hydrophore (zoology), see Haleciidae Hydraulic accumulator Hydrophobe Hydrophone This disambiguation page lists articles associated with the title Hydrophore...
level between the front and back pickup. Three such cardioid microphones/hydrophones could be orthogonally oriented as a collocated triad to improve the gain...
weaponry reinforced, while new technologies, such as ASDIC, Huff-Duff and hydrophones, were developed. At the start of World War II in 1939, the Royal Navy...
embodiments, is electrically amplified by a hydrophone. In one embodiment there is a further processing of each hydrophone signal. Embodiments with various kinds...
southern Indian Ocean (between Africa, Australia and Antarctica), by hydrophones in portions of all five major ocean basins and as distant as the North...
is used for 3D seismic data acquisition. The ship is equipped with 24 hydrophone streamer reels in two rows, with 16 reels astern, and eight further forward...
Iceland. The ships were forced to zigzag to avoid ice floes. At 19:22, hydrophone and radar operators aboard the German warships detected the cruiser HMS Suffolk...
ways of employing such communication but the most common is by using hydrophones. Underwater communication is difficult due to factors such as multi-path...
Reef region since the 60s. Most observations of activity have come from hydrophone recordings or seismograph recordings with very large location uncertainty...
noise-reduction). TP613, ca 1982: Development of the TP612 with passive-hydrophone target-seeker and pistol. Two-way data communications, and engine with...
technology for studying seamount eruptions did not exist until advancements in hydrophone technology made it possible to "listen" to acoustic waves, known as T-waves...
locations on the surface by what is known as receivers (geophones or hydrophones). Before seismic data can be acquired, a seismic survey needs to be planned...
(18 km/h) and 18 knots (33 km/h). The homing system consisted of two hydrophone receivers and altered the direction of the rudder via an electropneumatic...
infrared wavelengths, causing the greenhouse effect Gruppenhorchgerät, a hydrophone array which was used on Nazi Germany's U-boats Marshfield Municipal Airport...
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