Sonar image of of the minesweeper T-297, formerly the Latvian Virsaitis in waters 20 km from island Sonar (originally an for SOund Navigation And Ranging) is a technique that uses propagation (usually underwater, as in ) to, communicate with or detect objects on or under the surface of the water, such as other vessels. Two types of technology share the name 'sonar': passive sonar is essentially listening for the sound made by vessels; active sonar is emitting pulses of sounds and listening for echoes. Sonar may be used as a means of and of measurement of the echo characteristics of 'targets' in the water. Acoustic location in air was used before the introduction of. Sonar may also be used in air for robot navigation, and (an upward looking in-air sonar) is used for atmospheric investigations. The term sonar is also used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from very low () to extremely high ().

The study of underwater sound is known as. Contents • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • History Although some animals (dolphins and bats) have used sound for communication and object detection for millions of years, use by humans in the water is initially recorded by in 1490: a tube inserted into the water was said to be used to detect vessels by placing an ear to the tube.

In the framework of a prototype program launched by ESO, Micro-Epsilon has developed an inductive edge sensor based on Embedded Coil Technology whose. In addition the volume inside the cup can be flooded with nitrogen to get well defined, humidity free conditions.

In the 19th century an underwater bell was used as an ancillary to to provide warning of hazards. The use of sound to 'echo-locate' underwater in the same way as use sound for aerial navigation seems to have been prompted by the disaster of 1912. The world's first for an underwater echo ranging device was filed at the British by English meteorologist a month after the sinking of the Titanic, and a German physicist obtained a patent for an echo sounder in 1913.

The Canadian engineer, while working for the Submarine Signal Company in Boston, built an experimental system beginning in 1912, a system later tested in Boston Harbor, and finally in 1914 from the U.S. Revenue (now Coast Guard) Cutter Miami on the off Canada.

In that test, Fessenden demonstrated depth sounding, underwater communications () and echo ranging (detecting an iceberg at 2 miles (3 km) range). The so-called, at about 500 Hz frequency, was unable to determine the bearing of the berg due to the 3-metre wavelength and the small dimension of the transducer's radiating face (less than 1 metre in diameter).

The ten -built launched in 1915 were equipped with a Fessenden oscillator. During the need to detect prompted more research into the use of sound. The British made early use of underwater listening devices called, while the French physicist, working with a Russian immigrant electrical engineer Constantin Chilowsky, worked on the development of active sound devices for detecting submarines in 1915. Although and magnetostrictive transducers later superseded the transducers they used, this work influenced future designs. Lightweight sound-sensitive plastic film and fibre optics have been used for hydrophones (acousto-electric transducers for in-water use), while and PMN (lead magnesium niobate) have been developed for projectors.

ASDIC display unit around 1944 In 1916, under the British, Canadian physicist took on the active sound detection project with, producing a prototype for testing in mid-1917. This work, for the Anti-Submarine Division of the British Naval Staff, was undertaken in utmost secrecy, and used quartz piezoelectric crystals to produce the world's first practical underwater active sound detection apparatus. To maintain secrecy, no mention of sound experimentation or quartz was made – the word used to describe the early work ('supersonics') was changed to 'ASD'ics, and the quartz material to 'ASD'ivite: 'ASD' for 'Anti-Submarine Division', hence the British acronym ASDIC. In 1939, in response to a question from the, the Admiralty made up the story that it stood for 'Allied Submarine Detection Investigation Committee', and this is still widely believed, though no committee bearing this name has been found in the Admiralty archives.

By 1918, both and had built prototype active systems. The British tested their ASDIC on in 1920 and started production in 1922. The 6th Destroyer Flotilla had ASDIC-equipped vessels in 1923. An anti-submarine school and a training of four vessels were established on in 1924. The Sonar QB set arrived in 1931. By the outbreak of, the had five sets for different surface ship classes, and others for submarines, incorporated into a complete anti-submarine attack system.

The effectiveness of early ASDIC was hamstrung by the use of the as an anti-submarine weapon. This required an attacking vessel to pass over a submerged contact before dropping charges over the stern, resulting in a loss of ASDIC contact in the moments leading up to attack. The hunter was effectively firing blind, during which time a submarine commander could take evasive action. This situation was remedied by using several ships cooperating and by the adoption of 'ahead-throwing weapons', such as and later, which projected warheads at a target ahead of the attacker and thus still in ASDIC contact. Developments during the war resulted in British ASDIC sets that used several different shapes of beam, continuously covering blind spots. Later, were used.

At the start of, British ASDIC technology was to the United States. Research on ASDIC and underwater sound was expanded in the UK and in the US. Many new types of military sound detection were developed. These included, first developed by the British in 1944 under the High Tea, dipping/dunking sonar and detection sonar. This work formed the basis for post-war developments related to countering the.

Work on sonar had also been carried out in the, notably in, which included. At the end of World War II, this German work was assimilated by Britain and the U.S. Sonars have continued to be developed by many countries, including, for both military and civil uses. In recent years the major military development has been the increasing interest in low-frequency active sonar. SONAR During the 1930s American engineers developed their own underwater sound-detection technology, and important discoveries were made, such as, that would help future development. After technical information was exchanged between the two countries during the Second World War, Americans began to use the term SONAR for their systems, coined as the equivalent of. Materials and designs There was little progress in development from 1915 to 1940.

In 1940, the US sonars typically consisted of a transducer and an array of nickel tubes connected to a 1-foot-diameter steel plate attached back-to-back to a crystal in a spherical housing. This assembly penetrated the ship hull and was manually rotated to the desired angle. The Rochelle salt crystal had better parameters, but the magnetostrictive unit was much more reliable.

Early World War II losses prompted rapid research in the field, pursuing both improvements in magnetostrictive transducer parameters and Rochelle salt reliability. (ADP), a superior alternative, was found as a replacement for Rochelle salt; the first application was a replacement of the 24 kHz Rochelle-salt transducers. Within nine months, Rochelle salt was obsolete. The ADP manufacturing facility grew from few dozen personnel in early 1940 to several thousands in 1942. One of the earliest application of ADP crystals were hydrophones for; the crystals were specified for low-frequency cutoff at 5 Hz, withstanding mechanical shock for deployment from aircraft from 3,000 m (10,000 ft), and ability to survive neighbouring mine explosions.

One of key features of ADP reliability is its zero aging characteristics; the crystal keeps its parameters even over prolonged storage. Another application was for acoustic homing torpedoes. Two pairs of directional hydrophones were mounted on the torpedo nose, in the horizontal and vertical plane; the difference signals from the pairs were used to steer the torpedo left-right and up-down.

A countermeasure was developed: the targeted submarine discharged an chemical, and the torpedo went after the noisier fizzy decoy. The counter-countermeasure was a torpedo with active sonar – a transducer was added to the torpedo nose, and the microphones were listening for its reflected periodic tone bursts. The transducers comprised identical rectangular crystal plates arranged to diamond-shaped areas in staggered rows. Passive sonar arrays for submarines were developed from ADP crystals. Several crystal assemblies were arranged in a steel tube, vacuum-filled with, and sealed. The tubes then were mounted in parallel arrays. The standard US Navy scanning sonar at the end of World War II operated at 18 kHz, using an array of ADP crystals.

Desired longer range, however, required use of lower frequencies. The required dimensions were too big for ADP crystals, so in the early 1950s magnetostrictive and piezoelectric systems were developed, but these had problems achieving uniform impedance characteristics, and the beam pattern suffered. Barium titanate was then replaced with more stable (PZT), and the frequency was lowered to 5 kHz. The US fleet used this material in the AN/SQS-23 sonar for several decades. The SQS-23 sonar first used magnetostrictive nickel transducers, but these weighed several tons, and nickel was expensive and considered a critical material; piezoelectric transducers were therefore substituted.

The sonar was a large array of 432 individual transducers. At first, the transducers were unreliable, showing mechanical and electrical failures and deteriorating soon after installation; they were also produced by several vendors, had different designs, and their characteristics were different enough to impair the array's performance. The policy to allow repair of individual transducers was then sacrificed, and 'expendable modular design', sealed non-repairable modules, was chosen instead, eliminating the problem with seals and other extraneous mechanical parts. The Imperial Japanese Navy at the onset of World War II used projectors based on. These were big and heavy, especially if designed for lower frequencies; the one for Type 91 set, operating at 9 kHz, had a diameter of 30 inches (760 mm) and was driven by an oscillator with 5 kW power and 7 kV of output amplitude. The Type 93 projectors consisted of solid sandwiches of quartz, assembled into spherical bodies. The Type 93 sonars were later replaced with Type 3, which followed German design and used magnetostrictive projectors; the projectors consisted of two rectangular identical independent units in a cast iron rectangular body about 16 by 9 inches (410 mm × 230 mm).

The exposed area was half the wavelength wide and three wavelengths high. The magnetostrictive cores were made from 4 mm stampings of nickel, and later of an with aluminium content between 12.7% and 12.9%. The power was provided from a 2 kW at 3.8 kV, with polarization from a 20 V, 8 A DC source. The passive hydrophones of the Imperial Japanese Navy were based on moving-coil design, Rochelle salt piezo transducers, and. Magnetostrictive transducers were pursued after World War II as an alternative to piezoelectric ones. Nickel scroll-wound ring transducers were used for high-power low-frequency operations, with size up to 13 feet (4.0 m) in diameter, probably the largest individual sonar transducers ever. The advantage of metals is their high tensile strength and low input electrical impedance, but they have electrical losses and lower coupling coefficient than PZT, whose tensile strength can be increased.

Other materials were also tried; nonmetallic were promising for their low electrical conductivity resulting in low losses, offered high coupling coefficient, but they were inferior to PZT overall. In the 1970s, compounds of and iron were discovered with superior magnetomechanic properties, namely the alloy. This made possible new designs, e.g. A hybrid magnetostrictive-piezoelectric transducer.

The most recent sch [ ] material is. Other types of transducers include variable-reluctance (or moving-armature, or electromagnetic) transducers, where magnetic force acts on the surfaces of gaps, and moving coil (or electrodynamic) transducers, similar to conventional speakers; the latter are used in underwater sound calibration, due to their very low resonance frequencies and flat broadband characteristics above them. Active sonar. Principle of an active sonar Active sonar uses a sound transmitter and a receiver. When the two are in the same place it is monostatic operation.

When the transmitter and receiver are separated it is bistatic operation. Download Horoscope Explorer Pro Torrent. When more transmitters (or more receivers) are used, again spatially separated, it is multistatic operation. Most sonars are used monostatically with the same array often being used for transmission and reception. Active sonobuoy fields may be operated multistatically. Active sonar creates a of sound, often called a 'ping', and then listens for () of the pulse. This pulse of sound is generally created electronically using a sonar projector consisting of a signal generator, power amplifier and electro-acoustic transducer/array.

A beamformer is usually employed to concentrate the acoustic power into a beam, which may be swept to cover the required search angles. Generally, the electro-acoustic transducers are of the type and their design may be optimised to achieve maximum efficiency over the widest bandwidth, in order to optimise performance of the overall system. Occasionally, the acoustic pulse may be created by other means, e.g. (1) chemically using explosives, or (2) airguns or (3) plasma sound sources. To measure the distance to an object, the time from transmission of a pulse to reception is measured and converted into a range by knowing the speed of sound. To measure the, several are used, and the set measures the relative arrival time to each, or with an array of hydrophones, by measuring the relative amplitude in beams formed through a process called. Use of an array reduces the spatial response so that to provide wide cover systems are used.

The target signal (if present) together with noise is then passed through various forms of, which for simple sonars may be just energy measurement. It is then presented to some form of decision device that calls the output either the required signal or noise. This decision device may be an operator with headphones or a display, or in more sophisticated sonars this function may be carried out by software. Further processes may be carried out to classify the target and localise it, as well as measuring its velocity.

The pulse may be at constant or a of changing frequency (to allow on reception). Simple sonars generally use the former with a filter wide enough to cover possible Doppler changes due to target movement, while more complex ones generally include the latter technique. Since became available has usually been implemented using digital correlation techniques. Military sonars often have multiple beams to provide all-round cover while simple ones only cover a narrow arc, although the beam may be rotated, relatively slowly, by mechanical scanning. Particularly when single frequency transmissions are used, the can be used to measure the radial speed of a target. The difference in frequency between the transmitted and received signal is measured and converted into a velocity.

Since Doppler shifts can be introduced by either receiver or target motion, allowance has to be made for the radial speed of the searching platform. One useful small sonar is similar in appearance to a waterproof flashlight. The head is pointed into the water, a button is pressed, and the device displays the distance to the target. Another variant is a ' that shows a small display with of fish.

Some civilian sonars (which are not designed for stealth) approach active military sonars in capability, with quite exotic three-dimensional displays of the area near the boat. When active sonar is used to measure the distance from the transducer to the bottom, it is known as.

Similar methods may be used looking upward for wave measurement. Active sonar is also used to measure distance through water between two sonar transducers or a combination of a hydrophone (underwater acoustic microphone) and projector (underwater acoustic speaker). A transducer is a device that can transmit and receive acoustic signals ('pings').

When a hydrophone/transducer receives a specific interrogation signal it responds by transmitting a specific reply signal. To measure distance, one transducer/projector transmits an interrogation signal and measures the time between this transmission and the receipt of the other transducer/hydrophone reply. The time difference, scaled by the speed of sound through water and divided by two, is the distance between the two platforms. This technique, when used with multiple transducers/hydrophones/projectors, can calculate the relative positions of static and moving objects in water. In combat situations, an active pulse can be detected by an opponent and will reveal a submarine's position.

A very directional, but low-efficiency, type of sonar (used by fisheries, military, and for port security) makes use of a complex nonlinear feature of water known as non-linear sonar, the virtual transducer being known as a. Recording of active SONAR pings. Problems playing this file? Project Artemis was a one-of-a-kind low-frequency sonar for surveillance that was deployed off Bermuda for several years in the early 1960s. The active portion was deployed from a World War II tanker, and the receiving array was built into a fixed position on an offshore bank. Transponder This is an active sonar device that receives a stimulus and immediately (or with a delay) retransmits the received signal or a predetermined one. Performance prediction A sonar target is small relative to the, centred around the emitter, on which it is located.

Therefore, the power of the reflected signal is very low, several less than the original signal. Even if the reflected signal was of the same power, the following example (using hypothetical values) shows the problem: Suppose a sonar system is capable of emitting a 10,000 W/m 2 signal at 1 m, and detecting a 0.001 W/m 2 signal. At 100 m the signal will be 1 W/m 2 (due to the ). If the entire signal is reflected from a 10 m 2 target, it will be at 0.001 W/m 2 when it reaches the emitter, i.e. Just detectable. However, the original signal will remain above 0.001 W/m 2 until 300 m. Any 10 m 2 target between 100 and 300 m using a similar or better system would be able to detect the pulse, but would not be detected by the emitter.

The detectors must be very sensitive to pick up the echoes. Since the original signal is much more powerful, it can be detected many times further than twice the range of the sonar (as in the example). Active sonar have two performance limitations: due to noise and reverberation. In general, one or other of these will dominate, so that the two effects can be initially considered separately.

In noise-limited conditions at initial detection: SL − 2TL + TS − (NL − DI) = DT, where SL is the, TL is the (or ), TS is the, NL is the, DI is the of the array (an approximation to the ) and DT is the. In reverberation-limited conditions at initial detection (neglecting array gain): SL − 2TL + TS = RL + DT, where RL is the, and the other factors are as before. Hand-held sonar for use by a diver • The LIMIS (= Limpet Mine Imaging Sonar) is a hand-held or -mounted imaging sonar for use by a diver. Its name is because it was designed for patrol divers (combat or ) to look for in low water. • The LUIS (= Lensing Underwater Imaging System) is another imaging sonar for use by a diver. • There is or was a small flashlight-shaped handheld sonar for divers, that merely displays range. • For the INSS = Integrated Navigation Sonar System Passive sonar.

This section does not any. Unsourced material may be challenged and. (April 2010) () Passive sonar listens without transmitting. It is often employed in military settings, although it is also used in science applications, e.g., detecting fish for presence/absence studies in various aquatic environments - see also and.

In the very broadest usage, this term can encompass virtually any analytical technique involving remotely generated sound, though it is usually restricted to techniques applied in an aquatic environment. Identifying sound sources Passive sonar has a wide variety of techniques for identifying the source of a detected sound. For example, U.S. Vessels usually operate 60 power systems. If or are mounted without proper insulation from the or become flooded, the 60 Hz sound from the windings can be emitted from the or ship. This can help to identify its nationality, as all European submarines and nearly every other nation's submarine have 50 Hz power systems.

Intermittent sound sources (such as a being dropped) may also be detectable to passive sonar. Until fairly recently, [ ] an experienced, trained operator identified signals, but now computers may do this. Passive sonar systems may have large sonic, but the sonar operator usually finally classifies the signals manually. A frequently uses these databases to identify classes of ships, actions (i.e.

The speed of a ship, or the type of weapon released), and even particular ships. Publications for classification of sounds are provided by and continually updated by the.

Noise limitations Passive sonar on vehicles is usually severely limited because of noise generated by the vehicle. For this reason, many submarines operate that can be cooled without pumps, using silent, or or, which can also run silently.

Vehicles' are also designed and precisely machined to emit minimal noise. High-speed propellers often create tiny bubbles in the water, and this has a distinct sound. The sonar may be towed behind the ship or submarine in order to reduce the effect of noise generated by the watercraft itself. Towed units also combat the, as the unit may be towed above or below the. The display of most passive sonars used to be a two-dimensional. The horizontal direction of the display is bearing.

The vertical is frequency, or sometimes time. Another display technique is to color-code frequency-time information for bearing. More recent displays are generated by the computers, and mimic -type displays.

Performance prediction Unlike active sonar, only one-way propagation is involved. Because of the different signal processing used, the minimal detectable signal-to-noise ratio will be different. The equation for determining the performance of a passive sonar is SL − TL = NL − DI + DT, where SL is the source level, TL is the transmission loss, NL is the noise level, DI is the directivity index of the array (an approximation to the array gain) and DT is the detection threshold. The of a passive sonar is FOM = SL + DI − (NL + DT).

Performance factors The detection, classification and localisation performance of a sonar depends on the environment and the receiving equipment, as well as the transmitting equipment in an active sonar or the target radiated noise in a passive sonar. Sound propagation Sonar operation is affected by variations in, particularly in the vertical plane. Sound travels more slowly in than in, though the difference is small. The speed is determined by the water's and. The bulk modulus is affected by temperature, dissolved impurities (usually ), and. The density effect is small. The (in feet per second) is approximately: 4388 + (11.25 × temperature (in °F)) + (0.0182 × depth (in feet)) + salinity (in parts-per-thousand ).

This derived approximation equation is reasonably accurate for normal temperatures, concentrations of salinity and the range of most ocean depths. Ocean temperature varies with depth, but at between 30 and 100 meters there is often a marked change, called the, dividing the warmer surface water from the cold, still waters that make up the rest of the ocean. This can frustrate sonar, because a sound originating on one side of the thermocline tends to be bent, or, through the thermocline. The thermocline may be present in shallower coastal waters. However, wave action will often mix the water column and eliminate the thermocline. Water also affects sound propagation: higher pressure increases the sound speed, which causes the sound waves to refract away from the area of higher sound speed.

The mathematical model of refraction is called. If the sound source is deep and the conditions are right, propagation may occur in the '. This provides extremely low propagation loss to a receiver in the channel. This is because of sound trapping in the channel with no losses at the boundaries. Similar propagation can occur in the 'surface duct' under suitable conditions.

However, in this case there are reflection losses at the surface. In shallow water propagation is generally by repeated reflection at the surface and bottom, where considerable losses can occur.

Sound propagation is affected by in the water itself as well as at the surface and bottom. This absorption depends upon frequency, with several different mechanisms in sea water. Long-range sonar uses low frequencies to minimise absorption effects. The sea contains many sources of noise that interfere with the desired target echo or signature. The main noise sources are and. The motion of the receiver through the water can also cause speed-dependent low frequency noise.

See also: When active sonar is used, occurs from small objects in the sea as well as from the bottom and surface. This can be a major source of interference. This acoustic scattering is analogous to the scattering of the light from a car's headlights in fog: a high-intensity pencil beam will penetrate the fog to some extent, but broader-beam headlights emit much light in unwanted directions, much of which is scattered back to the observer, overwhelming that reflected from the target ('white-out'). For analogous reasons active sonar needs to transmit in a narrow beam to minimise scattering. Target characteristics The sound reflection characteristics of the target of an active sonar, such as a submarine, are known as its.

A complication is that echoes are also obtained from other objects in the sea such as whales, wakes, schools of fish and rocks. Passive sonar detects the target's radiated noise characteristics.

The radiated comprises a of noise with peaks at certain frequencies which can be used for classification. Countermeasures Active (powered) countermeasures may be launched by a submarine under attack to raise the noise level, provide a large false target, and obscure the signature of the submarine itself.

Passive (i.e., non-powered) countermeasures include: • Mounting noise-generating devices on isolating devices. • Sound-absorbent coatings on the hulls of submarines, for example. Military applications Modern makes extensive use of both passive and active sonar from water-borne vessels, aircraft and fixed installations. Although active sonar was used by surface craft in, submarines avoided the use of active sonar due to the potential for revealing their presence and position to enemy forces. However, the advent of modern signal-processing enabled the use of passive sonar as a primary means for search and detection operations. In 1987 a division of company reportedly sold machinery to the that allowed their submarine propeller blades to be milled so that they became radically quieter, making the newer generation of submarines more difficult to detect.

The use of active sonar by a submarine to determine bearing is extremely rare and will not necessarily give high quality bearing or range information to the submarines fire control team. However, use of active sonar on surface ships is very common and is used by submarines when the tactical situation dictates it is more important to determine the position of a hostile submarine than conceal their own position. With surface ships, it might be assumed that the threat is already tracking the ship with satellite data as any vessel around the emitting sonar will detect the emission. Having heard the signal, it is easy to identify the sonar equipment used (usually with its frequency) and its position (with the sound wave's energy). Active sonar is similar to radar in that, while it allows detection of targets at a certain range, it also enables the emitter to be detected at a far greater range, which is undesirable. Since active sonar reveals the presence and position of the operator, and does not allow exact classification of targets, it is used by fast (planes, helicopters) and by noisy platforms (most surface ships) but rarely by submarines.

When active sonar is used by surface ships or submarines, it is typically activated very briefly at intermittent periods to minimize the risk of detection. Consequently, active sonar is normally considered a backup to passive sonar. In aircraft, active sonar is used in the form of disposable that are dropped in the aircraft's patrol area or in the vicinity of possible enemy sonar contacts. Passive sonar has several advantages, most importantly that it is silent. If the target is high enough, it can have a greater range than active sonar, and allows the target to be identified. Since any motorized object makes some noise, it may in principle be detected, depending on the level of noise emitted and the in the area, as well as the technology used.

To simplify, passive sonar 'sees' around the ship using it. On a submarine, nose-mounted passive sonar detects in directions of about 270°, centered on the ship's alignment, the hull-mounted array of about 160° on each side, and the towed array of a full 360°.

The invisible areas are due to the ship's own interference. Once a signal is detected in a certain direction (which means that something makes sound in that direction, this is called broadband detection) it is possible to zoom in and analyze the signal received (narrowband analysis). This is generally done using a to show the different frequencies making up the sound. Since every engine makes a specific sound, it is straightforward to identify the object. Databases of unique engine sounds are part of what is known as acoustic intelligence or ACINT. Another use of passive sonar is to determine the target's.

This process is called (TMA), and the resultant 'solution' is the target's range, course, and speed. TMA is done by marking from which direction the sound comes at different times, and comparing the motion with that of the operator's own ship. Changes in relative motion are analyzed using standard geometrical techniques along with some assumptions about limiting cases.

Passive sonar is stealthy and very useful. However, it requires electronic components and is costly. It is generally deployed on expensive ships in the form of arrays to enhance detection.

Surface ships use it to good effect; it is even better used by, and it is also used by airplanes and helicopters, mostly to a 'surprise effect', since submarines can hide under thermal layers. If a submarine's commander believes he is alone, he may bring his boat closer to the surface and be easier to detect, or go deeper and faster, and thus make more sound. Examples of sonar applications in military use are given below. Many of the civil uses given in the following section may also be applicable to naval use. Anti-submarine warfare.

Variable Depth Sonar and its winch Until recently, ship sonars were usually with hull mounted arrays, either amidships or at the bow. It was soon found after their initial use that a means of reducing flow noise was required. The first were made of canvas on a framework, then steel ones were used. Now domes are usually made of reinforced plastic or pressurized rubber.

Such sonars are primarily active in operation. An example of a conventional hull mounted sonar is the. Because of the problems of ship noise, towed sonars are also used. These also have the advantage of being able to be placed deeper in the water. However, there are limitations on their use in shallow water. These are called towed arrays (linear) or variable depth sonars (VDS) with 2/3D arrays.

A problem is that the winches required to deploy/recover these are large and expensive. VDS sets are primarily active in operation while towed arrays are passive. An example of a modern active/passive ship towed sonar is made. Torpedoes Modern torpedoes are generally fitted with an active/passive sonar. This may be used to home directly on the target, but wake following torpedoes are also used. An early example of an acoustic homer was the. Torpedo countermeasures can be towed or free.

An early example was the German Sieglinde device while the was a chemical device. A widely used US device was the towed while (MOSS) was a free device. A modern alternative to the Nixie system is the system. Mines Mines may be fitted with a sonar to detect, localize and recognize the required target. Further information is given in and an example is the. Mine countermeasures Mine Countermeasure (MCM) Sonar, sometimes called 'Mine and Obstacle Avoidance Sonar (MOAS)', is a specialized type of sonar used for detecting small objects. Most MCM sonars are hull mounted but a few types are VDS design.

An example of a hull mounted MCM sonar is the while the and systems are VDS designs. See also Submarine navigation.

Main article: Submarines rely on sonar to a greater extent than surface ships as they cannot use radar at depth. The sonar arrays may be hull mounted or towed. Information fitted on typical fits is given in and submarine. Aircraft Helicopters can be used for antisubmarine warfare by deploying fields of active/passive sonobuoys or can operate dipping sonar, such as the.

Fixed wing aircraft can also deploy sonobuoys and have greater endurance and capacity to deploy them. Processing from the sonobuoys or can be on the aircraft or on ship. Dipping sonar has the advantage of being deployable to depths appropriate to daily conditions Helicopters have also been used for mine countermeasure missions using towed sonars such as the. AN/AQS-13 Dipping sonar deployed from an. Underwater communications Dedicated sonars can be fitted to ships and submarines for underwater communication. See also the section on the page. Ocean surveillance For many years, the operated a large set of passive sonar arrays at various points in the world's oceans, collectively called and later Integrated Undersea Surveillance System (IUSS).

A similar system is believed to have been operated by the Soviet Union. As permanently mounted arrays in the deep ocean were utilised, they were in very quiet conditions so long ranges could be achieved. Signal processing was carried out using powerful computers ashore.

With the ending of the Cold War a SOSUS array has been turned over to scientific use. In the United States Navy, a special badge known as the is awarded to those who have been trained and qualified in its operation. Underwater security Sonar can be used to detect and other. This can be applicable around ships or at entrances to ports. Active sonar can also be used as a deterrent and/or disablement mechanism.

One such device is the system. Hand-held sonar Limpet Mine Imaging Sonar (LIMIS) is a hand-held or -mounted imaging sonar designed for patrol divers (combat or ) to look for in low water. The LUIS is another imaging sonar for use by a diver. Integrated Navigation Sonar System (INSS) is a small flashlight-shaped handheld sonar for divers that displays range.

Intercept sonar This is a sonar designed to detect and locate the transmissions from hostile active sonars. An example of this is the Type 2082 fitted on the British. Civilian applications Fisheries is an important industry that is seeing growing demand, but world catch tonnage is falling as a result of serious resource problems. The industry faces a future of continuing worldwide consolidation until a point of can be reached.

However, the consolidation of the fishing fleets are driving increased demands for sophisticated fish finding electronics such as sensors, sounders and sonars. Historically, fishermen have used many different techniques to find and harvest fish. However, acoustic technology has been one of the most important driving forces behind the development of the modern commercial fisheries.

Sound waves travel differently through fish than through water because a fish's air-filled has a different density than seawater. This density difference allows the detection of schools of fish by using reflected sound.

Acoustic technology is especially well suited for underwater applications since sound travels farther and faster underwater than in air. Today, commercial fishing vessels rely almost completely on acoustic sonar and sounders to detect fish. Fishermen also use active sonar and echo sounder technology to determine water depth, bottom contour, and bottom composition. Cabin display of a fish finder sonar Companies such as eSonar, Raymarine UK, Marport Canada, Wesmar, Furuno, Krupp, and Simrad make a variety of sonar and acoustic instruments for the commercial fishing industry. For example, net sensors take various underwater measurements and transmit the information back to a receiver on board a vessel. Each sensor is equipped with one or more acoustic transducers depending on its specific function. Data is transmitted from the sensors using wireless acoustic telemetry and is received by a hull mounted hydrophone.

The are decoded and converted by a digital acoustic receiver into data which is transmitted to a bridge computer for on a high resolution monitor. Echo sounding. Main article: Echo sounding is a process used to determine the depth of water beneath and. A type of active sonar, echo sounding is the transmission of an acoustic pulse directly downwards to the seabed, measuring the time between transmission and echo return, after having hit the bottom and bouncing back to its ship of origin. The acoustic pulse is emitted by a transducer which receives the return echo as well. The depth measurement is calculated by multiplying the speed of sound in water(averaging 1,500 meters per second) by the time between emission and echo return. The value of underwater acoustics to the fishing industry has led to the development of other acoustic instruments that operate in a similar fashion to echo-sounders but, because their function is slightly different from the initial model of the echo-sounder, have been given different terms.

Net location The net sounder is an echo sounder with a transducer mounted on the headline of the net rather than on the bottom of the vessel. Nevertheless, to accommodate the distance from the transducer to the display unit, which is much greater than in a normal echo-sounder, several refinements have to be made. Two main types are available. The first is the cable type in which the signals are sent along a cable. In this case there has to be the provision of a cable drum on which to haul, shoot and stow the cable during the different phases of the operation. The second type is the cable less net-sounder – such as Marport’s Trawl Explorer - in which the signals are sent acoustically between the net and hull mounted receiver/hydrophone on the vessel.

In this case no cable drum is required but sophisticated electronics are needed at the transducer and receiver. The display on a net sounder shows the distance of the net from the bottom (or the surface), rather than the depth of water as with the echo-sounder's hull-mounted. Fixed to the headline of the net, the footrope can usually be seen which gives an indication of the net performance. Any fish passing into the net can also be seen, allowing fine adjustments to be made to catch the most fish possible.

In other fisheries, where the amount of fish in the net is important, catch sensor transducers are mounted at various positions on the cod-end of the net. As the cod-end fills up these catch sensor transducers are triggered one by one and this information is transmitted acoustically to display monitors on the bridge of the vessel. The skipper can then decide when to haul the net. Modern versions of the net sounder, using multiple element transducers, function more like a sonar than an echo sounder and show slices of the area in front of the net and not merely the vertical view that the initial net sounders used. The sonar is an echo-sounder with a directional capability that can show fish or other objects around the vessel.

ROV and UUV Small sonars have been fitted to Remotely Operated Vehicles (ROV) and Unmanned Underwater Vehicles (UUV) to allow their operation in murky conditions. These sonars are used for looking ahead of the vehicle. The is an UUV for MCM purposes. Vehicle location Sonars which act as beacons are fitted to aircraft to allow their location in the event of a crash in the sea. Short and Long Baseline sonars may be used for caring out the location, such as. Prosthesis for the visually impaired In 2013 an inventor in the United States unveiled a ' bodysuit, equipped with and systems, which alerts the wearer of incoming threats; allowing them to respond to attackers even when blindfolded. Scientific applications Biomass estimation.

Main article: Detection of fish, and other marine and aquatic life, and estimation their individual sizes or total biomass using active sonar techniques. As the sound pulse travels through water it encounters objects that are of different density or acoustic characteristics than the surrounding medium, such as fish, that reflect sound back toward the sound source.

These echoes provide information on fish size, location, abundance and behavior. Data is usually processed and analysed using a variety of software such as. See Also: and. Wave measurement An upward looking echo sounder mounted on the bottom or on a platform may be used to make measurements of wave height and period. From this statistics of the surface conditions at a location can be derived. Water velocity measurement Special short range sonars have been developed to allow measurements of water velocity.

Bottom type assessment Sonars have been developed that can be used to characterise the sea bottom into, for example, mud, sand, and gravel. Relatively simple sonars such as echo sounders can be promoted to seafloor classification systems via add-on modules, converting echo parameters into sediment type. Different algorithms exist, but they are all based on changes in the energy or shape of the reflected sounder pings. Advanced substrate classification analysis can be achieved using calibrated (scientific) echosounders and parametric or fuzzy-logic analysis of the acoustic data (See: ) Bathymetric mapping. Graphic depicting ship conducting and sonar operations can be used to derive maps of seafloor topography () by moving the sonar across it just above the bottom. Low frequency sonars such as have been used for continental shelf wide surveys while high frequency sonars are used for more detailed surveys of smaller areas.

Sub-bottom profiling Powerful low frequency echo-sounders have been developed for providing profiles of the upper layers of the ocean bottom. Synthetic aperture sonar Various synthetic aperture sonars have been built in the laboratory and some have entered use in mine-hunting and search systems. An explanation of their operation is given in.

Parametric sonar Parametric sources use the non-linearity of water to generate the difference frequency between two high frequencies. A virtual end-fire array is formed. Such a projector has advantages of broad bandwidth, narrow beamwidth, and when fully developed and carefully measured it has no obvious sidelobes: see.

Its major disadvantage is very low efficiency of only a few percent. Westervelt's seminal 1963 JASA paper summarizes the trends involved.

Sonar in extraterrestrial contexts Use of sonar has been proposed for determining the depth of hydrocarbon seas on. Effect of sonar on marine life Effect on marine mammals. Further information: Research has shown that use of active sonar can lead to mass strandings of., the most common casualty of the strandings, have been shown to be highly sensitive to mid-frequency active sonar. Other marine mammals such as the also flee away from the source of the sonar, while naval activity was suggested to be the most probable cause of a mass stranding of dolphins.

The US Navy, which part-funded some of studies, said that the findings only showed behavioural responses to sonar, not actual harm, but they 'will evaluate the effectiveness of [their] marine mammal protective measures in light of new research findings'. A 2008 US Supreme Court ruling on the use of sonar by the US Navy noted that there had been no cases where sonar had been conclusively shown to have harmed or killed a marine mammal. Some marine animals, such as and, use systems, sometimes called biosonar to locate predators and prey. Research on the effects of sonar on in the shows that mid-frequency sonar use disrupts the whales' feeding behavior. This indicates that sonar-induced disruption of feeding and displacement from high-quality prey patches could have significant and previously undocumented impacts on foraging ecology, individual and population health. Effect on fish High-intensity sonar sounds can create a small temporary shift in the hearing threshold of some fish.

Frequencies and resolutions The frequencies of sonars range from infrasonic to above a megahertz. Generally, the lower frequencies have longer range, while the higher frequencies offer better resolution, and smaller size for a given directionality. To achieve reasonable directionality, frequencies below 1 kHz generally require large size, usually achieved as towed arrays.

Low frequency sonars are loosely defined as 1–5 kHz, albeit some navies regard 5–7 kHz also as low frequency. Medium frequency is defined as 5–15 kHz. Another style of division considers low frequency to be under 1 kHz, and medium frequency at between 1–10 kHz. American World War II era sonars operated at a relatively high frequency of 20–30 kHz, to achieve directionality with reasonably small transducers, with typical maximum operational range of 2500 yd. Postwar sonars used lower frequencies to achieve longer range; e.g. SQS-4 operated at 10 kHz with range up to 5000 yd. SQS-26 and SQS-53 operated at 3 kHz with range up to 20,000 yd; their domes had size of approx.

A 60-ft personnel boat, an upper size limit for conventional hull sonars. Achieving larger sizes by conformal sonar array spread over the hull has not been effective so far, for lower frequencies linear or towed arrays are therefore used. Japanese WW2 sonars operated at a range of frequencies. The Type 91, with 30 inch quartz projector, worked at 9 kHz. The Type 93, with smaller quartz projectors, operated at 17.5 kHz (model 5 at 16 or 19 kHz magnetostrictive) at powers between 1.7 and 2.5 kilowatts, with range of up to 6 km. The later Type 3, with German-design magnetostrictive transducers, operated at 13, 14.5, 16, or 20 kHz (by model), using twin transducers (except model 1 which had three single ones), at 0.2 to 2.5 kilowatts.

The Simple type used 14.5 kHz magnetostrictive transducers at 0.25 kW, driven by capacitive discharge instead of oscillators, with range up to 2.5 km. The sonar's resolution is angular; objects further apart will be imaged with lower resolutions than nearby ones. Another source lists ranges and resolutions vs frequencies for sidescan sonars. 30 kHz provides low resolution with range of 1000–6000 m, 100 kHz gives medium resolution at 500–1000 m, 300 kHz gives high resolution at 150–500 m, and 600 kHz gives high resolution at 75–150 m. Longer range sonars are more adversely affected by nonhomogenities of water.

Some environments, typically shallow waters near the coasts, have complicated terrain with many features; higher frequencies become necessary there. As a specific example, the Sonar 2094 Digital, a towed fish capable of reaching depth of 1000 or 2000 meters, performs side-scanning at 114 kHz (600m range at each side, 50 by 1 degree beamwidth) and 410 kHz (150m range, 40 by 0.3 degree beamwidth), with 3 kW pulse power.

A JW Fishers system offers side-scanning at 1200 kHz with very high spatial resolution, optionally coupled with longer-range 600 kHz (range 200 ft at each side) or 100 kHz (up to 2000 ft per side, suitable for scanning large areas for big targets). • Hackmann, Willem. Seek & Strike: Sonar, anti-submarine warfare and the Royal Navy 1914-54.

London: Her Majesty's Stationery Office, 1984. • Hackmann, Willem D. 'Sonar Research and Naval Warfare 1914–1954: A Case Study of a Twentieth-Century Science'. Historical Studies in the Physical and Biological Sciences 16#1 (1986) 83–110. Principles of Underwater Sound, 3rd edition. (Peninsula Publishing, Los Altos, 1983). Fisheries Acoustics References • Fisheries Acoustics Research (FAR) at the University of Washington • NOAA Protocols for Fisheries Acoustics Surveys • —A 'how to' great reference for freshwater hydroacoustics for resource assessment • 'ACOUSTICS IN FISHERIES AND AQUATIC ECOLOGY' • 'Hydroacoustic Protocol - Lakes, Reservoirs and Lowland Rivers' (for fish assessment) • Simmonds, E.

Fisheries Acoustics: Theory and Practice, second edition. Fish and aquatic resources series, 10. Oxford: Blackwell Science, 2003.. Further reading •,, October 28, 1946.

An interesting account of the 4,800 ASDIC sonar devices secretly manufactured at,, during World War II. Retrieved 25 Sept. • one of the best general public articles on the subject External links Wikimedia Commons has media related to.

• • by Norwegian Defence Research Establishment (FFI) •.

(a standard tuned guitar) An electric guitar is a that uses one or more pickups to convert the vibration of its strings into electrical signals. The vibration occurs when a guitarist,,, or the strings. The used to sense the vibration generally uses to do so, though other technologies exist. In any case, the signal generated by an electric guitar is too weak to drive a, so it is sent to a before being sent to the speaker, which converts it into audible. Since the output of an electric guitar is an electric signal, it can be electronically altered by to change the of the sound. Often, the signal is modified using such as and, the latter effect is considered a key element of and guitar. Invented in 1931, the amplified electric guitar was adopted by, who wanted to play single-note in large ensembles.

Early proponents of the electric guitar on record included,,,, and. During the 1950s and 1960s, the electric guitar became the most important instrument in pop music.

It has evolved into an instrument that is capable of a multitude of sounds and styles in genres ranging from and to, and jazz. It served as a major component in the development of,, rock music, and many other genres of music. Electric guitar design and construction vary greatly in the shape of the body and the configuration of the neck, bridge, and pickups. Guitars may have a fixed or a spring-loaded hinged bridge that lets players 'bend' the pitch of notes or chords up or down or perform effects.

The sound of a guitar can be modified by such as,,, using, or guitar playing. There are several types of electric guitar, including the solid-body guitar, various types of hollow-body guitars, the (the most common type, usually tuned E, A, D, G, B, E, from lowest to highest strings), the, which typically adds a low B string below the low E, and the, which has six pairs of strings.

And rock groups often use the electric guitar in two roles: as a, which plays the sequence or and and sets the (as part of a ), and as a, which is used to perform instrumental lines, melodic, and. In a small group, such as a, one guitarist switches between both roles. In larger rock and metal bands, there is often a rhythm guitarist and a lead guitarist. Contents • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • History [ ] Many experiments at electrically amplifying the vibrations of a string instrument were made dating back to the early part of the 20th century. Patents from the 1910s show telephone transmitters were adapted and placed inside violins and to amplify the sound.

Hobbyists in the 1920s used attached to the; however, these detected vibration from the bridge on top of the instrument, resulting in a weak signal. With numerous people experimenting with electrical instruments in the 1920s and early 1930s, there are many claimants to have been the first to invent an electric guitar. The 'Frying Pan', 1932 Electric guitars were originally designed by acoustic guitar makers and instrument manufacturers. Some of the earliest electric guitars adapted instruments and used pickups.

The first electrically amplified guitar was designed in 1931 by, the general manager of the, with Paul Barth, who was vice president. Zee Tv Serial Mp3 Ringtones Free Download. The maple body prototype for the one-piece cast was built by Harry Watson, factory superintendent of the National Guitar Corporation. Commercial production began in late summer of 1932 by the Ro-Pat-In Corporation (Elect ro- Patent- Instrument Company), in Los Angeles, a partnership of Beauchamp, (originally Rickenbacher), and Paul Barth. In 1934, the company was renamed the Electro Stringed Instrument Company.

In that year Beauchamp applied for a United States patent for an Electrical Stringed Musical Instrument and the patent was issued in 1937. By early-mid 1935, Electro String Instrument Corporation had achieved mainstream success with the A-22 'Frying Pan' steel guitar, and set out to capture a new audience through its release of the and the, which was the first full 25' scale electric guitar produced.

The Electro-Spanish Ken Roberts provided players a full 25' scale, with 17 frets free of the fretboard. It is estimated that fewer than 50 Electro-Spanish Ken Roberts were constructed between 1933 and 1937; fewer than 10 are known to survive today. The need for the amplified guitar became apparent [ ] during the big band era as orchestras increased in size, particularly when acoustic guitars had to compete with large, loud sections.

[ ] The first electric guitars used in jazz were hollow acoustic guitar bodies with electromagnetic. Early electric guitar manufacturers include Rickenbacker in 1932; in 1933; National, and Volu-tone in 1934;, (Electrophone and Electar), and in 1935 and many others by 1936. Has one of the most often emulated electric guitar shapes The electric guitar is made of solid wood, without functionally resonating air spaces. The first solid-body was offered by no later than 1934. This model featured a guitar-shaped body of a single sheet of plywood affixed to a wood frame. Another early, substantially solid Spanish electric guitar, called the Electro Spanish, was marketed by the Rickenbacker guitar company in 1935 and made of. By 1936, the company introduced a wooden solid-body electric model, the Slingerland Songster 401 (and a lap steel counterpart, the Songster 400).

Gibson's first production electric guitar, marketed in 1936, was the model ('ES' for 'Electric Spanish', and '150' reflecting the $150 price of the instrument, along with matching amplifier). The ES-150 guitar featured a single-coil, hexagonally shaped 'bar' pickup, which was designed by Walt Fuller.

It became known as the 'Charlie Christian' pickup (named for the great jazz guitarist who was among the first to perform with the ES-150 guitar). The ES-150 achieved some popularity but suffered from unequal loudness across the six strings. Early proponents of the electric guitar on record include (Phil Spitalney Orchestra), ( Orchestra), (Andy Iona Orchestra), (under many aliases),,,,,, Charlie Christian ( Orchestra),,, and.

A functionally solid-body electric guitar was designed and built in 1940 by from an Epiphone acoustic archtop. His ' (so called because it consisted of a simple 4x4 wood post with a neck attached to it and homemade pickups and hardware, with two detachable Epiphone hollow-body halves attached to the sides for appearance only) shares nothing in design or hardware with the solid-body introduced in 1952. However, the feedback associated with hollow-bodied electric guitars was understood long before Paul's 'log' was created in 1940; Gage Brewer's Ro-Pat-In of 1932 had a top so heavily reinforced that it essentially functioned as a solid-body instrument. In 1945, Richard D. Bourgerie made an electric guitar pickup and amplifier for professional guitar player George Barnes.

Bourgerie worked through at Howard Radio Company, making electronic equipment for the American military. Barnes showed the result to Les Paul, who then arranged for Bourgerie to have one made for him. Construction [ ]. 1.1 1.2 cover 1.3 string guide 1.4 2. 2.1 2.2 inlay fret markers 2.3 2.4 neck joint 3. Body 3.1 'neck' 3.2 'bridge' pickup 3.3 saddles 3.4 3.5 fine tuners and 3.6 3.7 pickup selector switch 3.8 volume and tone control knobs 3.9 output connector (output jack)() 3.10 strap buttons 4.

4.1 bass strings 4.2 treble strings Electric guitar design and construction vary greatly in the shape of the body and the configuration of the neck, bridge, and pickups. However, some features are present on most guitars.

The photo below shows the different parts of an electric guitar. The (1) contains the metal (1.1), which use a for tuning. The (1.4)—a thin fret-like strip of metal, plastic, graphite or bone—supports the strings at the headstock end of the instrument. The (2.3) are thin metal strips that stop the string at the correct pitch when the player pushes a string against the fingerboard.

The (1.2) is a metal rod (usually adjustable) that counters the tension of the strings to keep the neck straight. Position markers (2.2) provide the player with a reference to the playing position on the fingerboard. The and (2.1) extend from the body. At the neck joint (2.4), the neck is either glued or bolted to the body. The body (3) is typically made of wood with a hard, polymerized finish. Strings vibrating in the magnetic field of the (3.1, 3.2) produce an electric current in the pickup winding that passes through the tone and volume (3.8) to the output jack.

Some guitars have pickups, in addition to or instead of magnetic pickups. Some guitars have a fixed (3.4). Others have a spring-loaded hinged bridge called a, tremolo bar, or whammy bar, which lets players bend notes or chords up or down in pitch or perform a embellishment.

A plastic on some guitars protects the body from scratches or covers the control cavity, which holds most of the wiring. The degree to which the choice of woods and other materials in the solid-guitar body (3) affects the sonic character of the amplified signal is disputed. Many believe it is highly significant, while others think the difference between woods is subtle. In acoustic and archtop guitars, wood choices more clearly affect tone.

Woods typically used in solid-body electric guitars include (brighter, but well rounded), swamp ash (similar to alder, but with more pronounced highs and lows), mahogany (dark, bassy, warm), poplar (similar to alder), and basswood (very neutral). Maple, a very bright tonewood, is also a popular body wood, but is very heavy. For this reason it is often placed as a 'cap' on a guitar made primarily of another wood. Cheaper guitars are often made of cheaper woods, such as plywood, pine or —not true hardwoods—which can affect durability and tone. Though most guitars are made of wood, any material may be used. Materials such as plastic, metal, and even cardboard have been used in some instruments. The guitar output jack typically provides a monaural signal.

Many guitars with active electronics use a jack with an extra contact normally used for stereo. These guitars use the extra contact to break the ground connection to the on-board battery to preserve battery life when the guitar is unplugged. These guitars require a mono plug to close the internal switch and connect the battery to ground. Standard guitar cables use a high-impedance 1/4-inch (6.35-mm) mono plug.

These have a tip and sleeve configuration referred to as a. The voltage is usually around 1 to 9 millivolts. A few guitars feature stereo output, such as guitars equipped with Rick-O-Sound.

There are a variety of ways the 'stereo' effect may be implemented. Commonly, but not exclusively, stereo guitars route the neck and bridge pickups to separate output buses on the guitar. A stereo cable then routes each pickup to its own signal chain or amplifier.

For these applications, the most popular connector is a high-impedance 1/4-inch plug with a tip, ring and sleeve configuration, also known as a. Some studio instruments, notably certain models, incorporate a low-impedance three-pin for. Many exotic arrangements and connectors exist that support features such as midi and pickups. Bridge and tailpiece systems [ ] The and, while serving separate purposes, work closely together to affect playing style and tone. There are four basic types of bridge and tailpiece systems on electric guitars. Within these four types are many variants. Hard-tail [ ] A guitar bridge anchors the strings at or directly behind the bridge and is fastened securely to the top of the instrument.

These are common on carved-top guitars, such as the and the, and on slab-body guitars, such as the and that are not equipped with a vibrato arm. Floating tailpiece [ ] A floating or trapeze (similar to a violin's) fastens to the body at the base of the guitar. These appear on,,, a wide variety of, particularly, and the 1952 Gibson Les Paul. Vibrato arms [ ] Pictured is a or style bridge and tailpiece system, often called a whammy bar or trem. It uses a lever ('vibrato arm') attached to the bridge that can temporarily slacken or tighten the strings to alter the.

A player can use this to create a vibrato or a effect. Early vibrato systems were often unreliable and made the guitar go out of tune easily.

They also had a limited pitch range. Later designs were better, but Fender held the patent on these, so other companies used older designs for many years. Detail of a Squier-made Fender Stratocaster. Note the vibrato arm, the 3 single-coil pickups, the volume and tone knobs.

With expiration of the Fender patent on the -style vibrato, various improvements on this type of internal, multi-spring vibrato system are now available. Introduced one of the first improvements on the vibrato system in many years when, in the late 1970s, he experimented with 'locking' nuts and bridges that prevent the guitar from losing tuning, even under heavy vibrato bar use. String-through body [ ].

Tune-o-matic with 'strings through the body' construction (without stopbar) The fourth type of system employs string-through body anchoring. The strings pass over the bridge saddles, then through holes through the top of the guitar body to the back. The strings are typically anchored in place at the back of the guitar by metal.

Many believe this design improves a guitar's and. A few examples of string-through body guitars are the, the, the IT Warlock and Mockingbird, and the Omen 6 and 7 series. Main article: Compared to an acoustic guitar, which has a hollow body, electric guitars make much less audible sound when their strings are plucked, so electric guitars are normally plugged into a guitar amplifier and speaker. When an electric guitar is played, string movement produces a signal by generating (i.e., ) a small electric current in the magnetic pickups, which are wound with coils of very fine wire. The signal passes through the tone and volume circuits to the output jack, and through a cable to an. The current induced is proportional to such factors as string density and the amount of movement over the pickups.

Pickups on a Fender Squier 'Fat Strat' guitar—a 'humbucker' pickup on the left and two single-coil pickups on the right. Because in most cases it is desirable to isolate coil-wound pickups from the unintended sound of internal vibration of loose coil windings, a guitar's magnetic pickups are normally embedded or 'potted' in wax,, or to prevent the pickup from producing a effect. Because of their natural inductive qualities, all magnetic pickups tend to pick up ambient, usually unwanted or EMI. The resulting is particularly strong with single-coil pickups, and it is aggravated by the fact that many vintage guitars are insufficiently shielded against electromagnetic interference. The most common source is 50- or 60- hum from systems (house wiring, etc.).

Since nearly all amplifiers and audio equipment associated with electric guitars must be plugged in, it is a continuing technical challenge to reduce or eliminate unwanted hum. Double-coil or ' pickups were invented as a way to reduce or counter the unwanted ambient hum sounds (known as 60-cycle hum).

Humbuckers have two coils of opposite magnetic and electric polarity to produce a signal. Electromagnetic noise that hits both coils equally tries to drive the pickup signal toward positive on one coil and toward negative on the other, which cancels out the noise. The two coils are wired in phase, so their signal adds together. This high combined of the two coils leads to the richer, 'fatter' tone associated with humbucking pickups. Use a 'sandwich' of quartz crystal or other piezoelectric material, typically placed beneath the string saddles or nut.

These devices respond to pressure changes from all vibration at these specific points. Are a type of pickup that sense string and body vibrations using infrared light. These pickups are not sensitive to EMI. Some 'hybrid' electric guitars are equipped with additional, piezoelectric, optical, or other types of to approximate an acoustic instrument tone and broaden the sonic palette of the instrument. Guitar necks [ ] Electric guitar necks vary in composition and shape.

The primary metric of guitar necks is the scale length, which is the vibrating length of the strings from nut to bridge. A typical Fender guitar uses a 25.5-inch scale length, while Gibson uses a 24.75-inch scale length in their. While the scale length of the Les Paul is often described as 24.75 inches, it has varied through the years by as much as a half inch. [ ] Frets are positioned proportionally to scale length—the shorter the scale length, the closer the fret spacing.

Opinions vary regarding the effect of scale length on tone and feel. Popular opinion holds that longer scale length contributes to greater. Reports of playing feel are greatly complicated by the many factors involved in this perception. String gauge and design, neck construction and relief, guitar setup, playing style and other factors contribute to the subjective impression of playability or feel.

A bolt-on neck Necks are described as,, or, depending on how they attach to the body. Set-in necks are glued to the body in the factory.

They are said to have a warmer tone and greater sustain. [ ] This is the traditional type of joint. Pioneered bolt-on necks on electric guitars to facilitate easy adjustment and replacement.

Neck-through instruments extend the neck the length of the instrument, so that it forms the center of the body, and are known for long sustain and for being particularly sturdy. [ ] While a set-in neck can be carefully unglued by a skilled, and a bolt-on neck can simply be unscrewed, a neck-through design is difficult or even impossible to repair, depending on the damage. Historically, the bolt-on style has been more popular for ease of installation and adjustment. Since bolt-on necks can be easily removed, there is an after-market in replacement bolt-on necks from companies such as Warmoth and Mighty Mite.

Some instruments—notably most Gibson models—continue to use set-in glued necks. Neck-through bodies are somewhat more common in bass guitars. Materials for necks are selected for dimensional stability and rigidity, and some allege that they influence tone. Hardwoods are preferred, with,, and topping the list. The neck and fingerboard can be made from different materials; for example, a guitar may have a maple neck with a or fingerboard. In the 1970s, designers began to use exotic man-made materials such as,, and.

Makers known for these unusual materials include,,, and. Aside from possible engineering advantages, some feel that in relation to the rising cost of rare, man-made materials may be economically preferable and more ecologically sensitive. However, wood remains popular in production instruments, though sometimes in conjunction with new materials., for example, use a wooden neck reinforced by embedding a light, carbon fiber rod in place of the usual heavier steel bar or adjustable steel truss rod.

After-market necks made entirely from carbon fiber fit existing bolt-on instruments. Few, if any, extensive formal investigations have been widely published that confirm or refute claims over the effects of different woods or materials on electric guitar sound. A neck-through bass guitar Several neck shapes appear on guitars, including shapes known as C necks, U necks, and V necks. These refer to the cross-sectional shape of the neck (especially near the nut). Several sizes of fret wire are available, with traditional players often preferring thin frets, and metal shredders liking thick frets. Thin frets are considered better for playing chords, while thick frets allow lead guitarists to bend notes with less effort.

An electric guitar with a folding neck called the 'Foldaxe' was designed and built for Chet Atkins. Guitars developed a line of exotic, carbon fiber instruments without headstocks, with tuning done on the bridge instead. Fingerboards vary as much as necks. The fingerboard surface usually has a cross-sectional radius that is optimized to accommodate finger movement for different playing techniques. Fingerboard radius typically ranges from nearly flat (a very large radius) to radically arched (a small radius).

The vintage, for example, has a typical small radius of approximately 7.25 inches. Some manufacturers have experimented with fret profile and material, fret layout, number of frets, and modifications of the fingerboard surface for various reasons. Some innovations were intended to improve playability by ergonomic means, such as ' compound radius fingerboard. Scalloped fingerboards added enhanced during fast legato runs. Fanned frets intend to provide each string with an optimal playing tension and enhanced musicality. Some guitars have no frets—and others, like the, have no neck in the traditional sense.

Sound and effects [ ] While an 's sound depends largely on the vibration of the guitar's body and the air inside it, the sound of an electric guitar depends largely on the signal from the pickups. The signal can be ' on its path to the via a range of effect devices or circuits that modify the tone and characteristics of the signal. Amplifiers and speakers also add coloration to the final sound. Built-in sound shaping [ ] Electric guitars usually [ ] have one to four magnetic pickups. Identical pickups produce different tones depending on location between the neck and bridge. Bridge pickups produce a bright or trebly timbre, and neck pickups are warmer [ ] or more bassy. The type of pickup also affects tone.

Dual-coil pickups sound warm, [ ] thick, [ ] perhaps even muddy [ ]; single-coil pickups sound clear, [ ] bright, [ ] perhaps even biting. [ ] Guitars don't require a uniform pickup type: a common [ ] mixture is the ' arrangement of one dual-coil at the bridge position and single coils in the middle and neck positions, known as HSS (humbucker/single/single). Some guitars have a piezoelectric pickup in addition to electromagnetic pickups.

Piezo pickups produce a more acoustic sound. The piezo runs through a built-in to improve similitude and control tone.

A blend knob controls the mix between electromagnetic and piezoelectric sounds. [ ] Where there is more than one pickup, a pickup selector switch is usually present to select or combine the outputs of two or more pickups, so that two-pickup guitars have three-way switches, and three-pickup guitars have five-way switches (a Gibson Les Paul three-pickup Black Beauty has a three-position toggle switch that configures bridge, bridge and middle [switch in middle position] and neck pickups). Further circuitry sometimes combines pickups in different ways. For instance, phase switching places one pickup out of with the other(s), leading to a 'honky', [ ] 'nasal', [ ] or ' [ ] sound.

Individual pickups can also have their timbre altered by switches, typically switches that effectively short-circuit some of a dual-coil pickup's windings [ ] to produce a tone similar to a single-coil pickup (usually done with push-pull volume knobs). The final stages of on-board sound-shaping circuitry are the volume control () and tone control (a low-pass filter which 'rolls off' the treble frequencies). Where there are individual volume controls for different pickups, and where pickup signals can be combined, they would affect the timbre of the final sound by adjusting the balance between pickups from a straight 50:50. The strings fitted to the guitar also have an influence on tone. Rock musicians often [ ] prefer the lightest gauge of, which is easier to, while jazz musicians go for heavier, strings, which have a rich, dark sound.

Steel, nickel, and cobalt are common string materials, and each gives a slightly different tone color. Recent guitar designs may incorporate much more complex circuitry than described above; see Digital and synthesizer guitars, below. Guitar amplifier [ ]. Main article: The solid-body electric guitar does not produce enough sound for an audience to hear it in a performance setting unless it's electronically amplified—plugged into an,,.

Guitar amplifier design uses a different approach than and home stereo systems. Audio amplifiers generally are intended to accurately reproduce the source signal without adding unwanted tonal coloration (i.e., they have a flat frequency response) or unwanted distortion. In contrast, most guitar amplifiers provide tonal coloration and overdrive or distortion of various types. A common tonal coloration sought by guitarists is rolling off some of the high frequencies. Along with a guitarist's playing style and choice of electric guitar and pickups, the choice of guitar amp model is a key part of a guitarist's unique tone. Many top guitarists are associated with a specific brand of guitar amp.

As well, electric guitarists in blues, rock and many related sub-genres often intentionally choose amplifiers or with controls that distort or alter the sound (to a greater or lesser degree). In the 1950s and 1960s, some guitarists began exploring a wider range of tonal effects by the sound of the instrument.

To do this, they used — increasing the of the beyond the level where the signal could be reproduced with little distortion, resulting in a 'fuzzy' sound. This effect is called ' by sound engineers, because when viewed with an, the wave forms of a distorted signal appear to have had their peaks 'clipped off', in the process introducing additional tones (often approximating the harmonics characteristic of a of that basic frequency). This was not actually a new development in the musical instrument or its supporting gear, but rather a shift of, such sounds not having been thought desirable previously.

Some distortion modes with an electric guitar increase the sustain of single notes and chords, which changes the sound of the instrument. In particular, distortion made it more feasible to perform guitar solos that used long, sustained notes. After distortion became popular amongst rock music groups, manufacturers included various provisions for it as part of amplifier design, making amps easier to overdrive, and providing separate 'dirty' and 'clean' channels so that distortion could easily be switched on and off.

The distortion characteristics of amplifiers are particularly sought-after in and many rock music genres, and various attempts have been made to emulate them without the disadvantages (e.g., fragility, low power, expense) of actual tubes. Distortion, especially in tube based amplifiers, can come from several sources: power supply sag as more power is demanded than the supply can provide at a steady voltage, deliberate gain over drive of active elements, or alterations in the feedback provisions for various circuit stages. Guitar amplifiers have long included at least a few, often tone controls for bass and treble, an integrated system (sometimes incorrectly labeled (and marketed) as ), or a mechanical unit. In the 2010s, guitar amps often have onboard effects. Some 2010-era amps provide multiple effects, such as chorus, flanger, phaser and octave down effects. The use of offboard effects such as stompbox pedals is made possible by either plugging the guitar into the external effect pedal and then plugging the effect pedal into the amp, or by using one or more, an arrangement that lets the player switch effects (electrically or mechanically) in or out of the signal path. In the signal chain, the effects loop is typically between the preamplifier stage and the power amplifier stages (though reverb units generally precede the effects loop an amplifier has both).

This lets the guitarist add effects to the signal after it passed through the preamplifier—which can be desirable, particularly with time-based effects such as delay. By the 2010s, guitar amplifiers usually included a distortion effect. Effects circuitry (whether internal to an amplifier or not) can be taken as far as amp modeling, by which is meant alteration of the electrical and audible behavior in such a way as to make an amp sound as though it were another (or one of several) amplifiers. When done well, a solid state amplifier can sound like a tube amplifier (even one with power supply sag), reducing the need to manage more than one amp. Some modeling systems even attempt to emulate the sound of different speakers/cabinets. Nearly all amp and speaker cabinet modeling is done digitally, using computer techniques (e.g., Digital Signal Processing or circuitry and software).

There is disagreement about whether this approach is musically satisfactory, and also whether this or that unit is more or less successful than another. Effects units [ ].

A Boss distortion pedal in use In the 1960s, the of the electric guitar was further modified by introducing in its signal path, before the guitar amp, of which one of the earliest units was the. Effects units come in several formats, the most common of which are the 'pedal' and the unit. A stomp box (or pedal) is a small metal or plastic box containing the circuitry, which is placed on the floor in front of the musician and connected in line with the patch cord connected to the instrument. The box is typically controlled by one or more foot-pedal on-off switches and it typically contains only one or two effects. Pedals are smaller than rackmount effects and usually less expensive. ' are used by musicians who use multiple stomp-boxes; these may be a project made with or a commercial stock or custom-made pedalboard. A rackmount effects unit may contain an electronic circuit nearly identical to a stompbox-based effect, but it is mounted in a standard 19' equipment rack, which is usually mounted in a that is designed to protect the equipment during transport.

More recently, as signal-processing technology continuously becomes more feature-dense, rack-mount effects units frequently contain several types of effects. They are typically controlled by knobs or switches on the front panel, and often by a digital control interface.

The Zoom 505 multi-effect pedal A multi-effects device (also called a 'multi-FX' device) is a single electronics effects pedal or rack-mount device that contains many electronic effects. In the late 1990s and throughout the 2000s, multi-FX manufacturers such as and produced devices that were increasingly feature-laden.

Multi-FX devices combine several effects together, and most devices allow users to use preset combinations of effects, including distortion, chorus, reverb, compression, and so on. This allows musicians to have quick on-stage access to different effects combinations.

Some multi-FX pedals contain modelled versions of well-known effects pedals or amplifiers. The Boss GT-8, a higher-end multi-effect processing pedal; note the preset switches and patch bank foot switches and built-in expression pedal.

Multi-effects devices have garnered a large share of the effects device market, because they offer the user such a large variety of effects in a single package. A low-priced multi-effects pedal may provide 20 or more effects for the price of a regular single-effect pedal. More expensive multi-effect pedals may include 40 or more effects, amplifier modelling, and the ability to combine effects or modelled amp sounds in different combinations, as if the user was using multiple guitar amps.

More expensive multi-effects pedals may also include more input and output jacks (e.g., an auxiliary input or a 'dry' output), MIDI inputs and outputs, and an expression pedal, which can control volume or modify effect parameters (e.g., the rate of the simulated rotary speaker effect). By the 1980s and 1990s, software effects became capable of replicating the analog effects used in the past. These new digital effects attempt to model the sound produced by analog effects and tube amps, with varying degrees of quality. There are many free guitar effects computer programs that can be downloaded from the Internet. Now, computers with sound cards can be used as digital guitar effects processors.

Although digital and software effects offer many advantages, many guitarists still use analog effects. Synthesizer and digital guitars [ ] In 2002, Gibson announced the first digital guitar, which performs analog-to-digital conversion internally. The resulting digital signal is delivered over a standard cable, eliminating cable-induced line noise. The guitar also provides independent signal processing for each individual string. In 2003, modelling maker Line 6 introduced the guitar. It differs in some fundamental ways from conventional solid-body electrics.

It has on-board electronics capable of modelling the sound of a variety of unique guitars and some other stringed instruments. At one time, some models featured piezoelectric pickups instead of the conventional electromagnetic pickups. Playing techniques [ ]. A The sound of a guitar can not only be adapted by electronic sound effects but is also heavily affected by various new techniques developed or becoming possible in combination with electric amplification. This is called.

Extended techniques include: •. This is not unique to the electric instrument, but it is greatly facilitated by the light strings typically used on solid-body guitars. • Neck bending, by holding the upper arm on the guitar body and bending the neck either to the front or pulling it back. This is used as a substitute for a tremolo bar, although not as effective, and the use of too much force could snap the guitar neck. • The use of the (whammy bar or tremolo arm), including the extreme technique of. The tremolo arm varies string tension to raise or lower pitch.

Instead of bending individual notes, this lets the player bend all notes at once to sound lower or higher. •, in which both hands are applied to the fretboard.

Tapping may be performed either one-handed or two-handed. It is an extended technique, executed by using one hand to tap the strings against the fingerboard, thus producing legato notes. Tapping usually incorporates pull-offs or hammer-ons as well, where the fingers of the left hand play a sequence of notes in synchronization with the tapping hand.

• the string with the fretting hand. The hammer-on technique • or, sometimes called 'squealies'.

This technique involves adding the edge of the thumb or the tip of the index finger on the picking hand to the regular picking action, resulting in a high-pitched sound. •, in which the volume knob is repeatedly rolled to create a violin-like sound. The same result can also be accomplished through the use of an external, although the knob technique can enhance showmanship and conveniently eliminate the need for another pedal.

• Use of to enhance sustain and change timbre. Feedback has become a striking characteristic of rock music, as electric guitar players such as, and deliberately induced feedback by holding their guitars close to the. Created his 1975 album entirely from loops of feedback played at various speeds. A good example of feedback can be heard on 's performance of 'Can You See Me?'

The entire guitar solo was created using amplifier feedback. • Substitution of another device for the, for instance the cello bow (as famously used by ) and the, a device using electromagnetic to vibrate strings without direct contact. Like feedback, these techniques increase sustain, bring out and change the acoustic. • built into the guitar itself.

Palm muting of the strings using the picking hand • Use of a. The term slide refers to the motion of the slide against the strings, while bottleneck refers to the material originally used for such slides: the necks of glass bottles.

Instead of altering the of a string in the normal manner (by pressing the string against a fret), a slide is placed upon the string to vary its vibrating length and thus its pitch. The slide can be moved along the string without lifting, creating continuous transitions in pitch.

• Sometimes guitars are even adapted with extra modifications to alter the sound, such as and. Unlike acoustic guitars, electric guitars have no vibrating soundboard to amplify string vibration. Instead, solid-body instruments depend on electric pickups and an (or amp) and. The solid body ensures that the amplified sound reproduces the string vibration alone, thus avoiding the and unwanted associated with amplified acoustic guitars. These guitars are generally made of hardwood covered with a hard finish, often polyester or lacquer. In large production facilities, the wood is stored for three to six months in a wood-drying before being cut to shape. Premium custom-built guitars are frequently made with much older, hand-selected wood.

[ ] One of the first solid-body guitars was invented. Did not present their guitar prototypes to the public, as they did not believe the solid-body style would catch on. Another early solid-body Spanish style guitar, resembling what would become Gibson's Les Paul guitar a decade later, was developed in 1941 by O.W. Appleton, of Nogales, Arizona. Appleton made contact with both Gibson and Fender but was unable to sell the idea behind his 'App' guitar to either company.

In 1946, commissioned steel guitar builder to build him a solid-body Spanish-style electric. Bigsby delivered the guitar in 1948. The first mass-produced solid-body guitar was and (later to become the ), first made in 1948, five years after Les Paul made his.

The Gibson Les Paul appeared soon after to compete with the Broadcaster. Another notable solid-body design is the, which was introduced in 1954 and became extremely popular among musicians in the 1960s and 1970s for its wide tonal capabilities and more comfortable ergonomics than other models. Chambered-body [ ] Some solid-bodied guitars, such as the Supreme, the Singlecut, and the, among others, are built with hollows in the body. These hollows are designed specifically not to interfere with the critical bridge and string anchor point on the solid body. In the case of Gibson and PRS, these are called chambered bodies. The motivation for this may be to reduce weight, to achieve a semi-acoustic tone (see below) or both.

Semi-acoustic [ ]. Epiphone semi-acoustic hollow-body guitar Semi-acoustic guitars have a hollow body (similar in depth to a solid-body guitar) and electronic pickups mounted on the body. They work in a similar way to solid-body electric guitars except that, because the hollow body also vibrates, the pickups convert a combination of string and body vibration into an electrical signal. Whereas chambered guitars are made, like solid-body guitars, from a single block of wood, semi-acoustic and full-hollowbody guitars bodies are made from thin sheets of wood. They do not provide enough acoustic volume for live performance, but they can be used unplugged for quiet practice.

Semi-acoustics are noted for being able to provide a sweet, plaintive, or funky tone. They are used in many genres, including blues,, sixties pop, and. They generally have cello-style. These can be blocked off to prevent feedback, as in 's famous. Feedback can also be reduced by making them with a solid block in the middle of the soundbox.

Full hollow-body [ ]. Main article: Full hollow-body guitars have large, deep bodies made of glued-together sheets, or 'plates', of wood. They can often be played at the same volume as an acoustic guitar and therefore can be used unplugged at intimate gigs. They qualify as electric guitars inasmuch as they have fitted pickups. Historically, archtop guitars with pickups were among the very earliest electric guitars. The instrument originated during the, in the 1920s and 1930s, and are still considered the classic (nicknamed 'jazzbox'). Like semi-acoustic guitars, they often have.

Having humbucker pickups (sometimes just a neck pickup) and usually strung heavlly, jazzboxes are noted for their warm, rich tone. A variation with single-coil pickups, and sometimes with a, has long been popular in and; it has a distinctly more twangy, biting tone than the classic jazzbox. The term refers to a method of construction subtly different from the typical acoustic (or ): the top is formed from a moderately thick (1 inch or 2–3 cm) piece of wood, which is then carved into a thin (0.1 in, or 2–3 mm) domed shape, whereas conventional acoustic guitars have a thin, flat top. Electric acoustic [ ]. Main article: Some are fitted with purely as an alternative to using a separate microphone. They may also be fitted with a pickup under the bridge, attached to the bridge mounting plate, or with a low-mass (usually a condenser mic) inside the body of the guitar that converts the vibrations in the body into electronic signals.

Combinations of these types of pickups may be used, with an integral mixer/preamp/graphic equalizer. Such instruments are called. They are regarded as acoustic guitars rather than electric guitars, because the pickups do not produce a signal directly from the vibration of the strings, but rather from the vibration of the guitar top or body. Electric acoustic guitars should not be confused with, which have pickups of the type found on solid-body electric guitars, or solid-body with piezoelectric pickups.

String, bridge, and neck variants [ ] One-string [ ] The one-string guitar is also known as the. Although rare, the one-string guitar is sometimes heard, particularly in, where improvised folk instruments were popular in the 1930s and 1940s. Had some regional success. [ ] Mississippi musician played a similar, homemade instrument. In a more contemporary style, Little Willie Joe, the inventor of the, had a hit in the 1950s with 'Twitchy', recorded with the Rene Hall Orchestra. Four-string [ ] The four-string guitar is better known as the.

One of its best-known players was, who played on with the and played a major role in the Prestige Blues Swingers. Multi-instrumentalist of and is a contemporary player who includes a tenor guitar in his repertoire. The four-string guitar is normally tuned CGDA, but some players, such as Tiny Grimes, tune to DGBE to preserve familiar 6-string guitar chord fingerings.

The tenor guitar can also be tuned like a soprano, concert, or tenor ukulele, using versions of GCEA tuning. Seven-string [ ]. Stephen Carpenter playing a 7-string electric guitar in 2009 Most seven-string guitars add a low B string below the low E. Both electric and exist designed for this tuning. A high A string above the high E instead of the low B string is sometimes used. Another less common seven-string arrangement is a second G string situated beside the standard G string and tuned an octave higher, in the same manner as a twelve-stringed guitar (see below).

Using a seven-string include,, and his son. Seven-string electric guitars were popularized among rock players in the 1980s. Along with the Japanese guitar company, Vai created the series seven-string guitars in the 1980s, with a double locking tremolo system for a seven-string guitar. These models were based on Vai's six-string signature series, the. Seven-string guitars experienced a resurgence in popularity in the 2000s, championed by,,,,,,, and other and bands.

Metal musicians often prefer the seven-string guitar for its extended lower range. The seven-string guitar has also played an essential role in rock and is commonly used in bands such as and and by experimental guitarists such as Ben Levin. Eight- and nine-string [ ]. Main article: Eight-string electric guitars are rare but not unused. One is played by, which was manufactured. The largest manufacturer of eight- to 14-string instruments is Warr Guitars. Their models are used by (ex ), who has his own signature line from the company.

Similarly, and of used 8-string guitars made by Nevborn Guitars and now guitars. Of the band is also known to use seven-string Ibanez guitars, and it is rumored that he is planning to release a K8 eight-string guitar similar to his K7 seven-string guitar. Another Ibanez player is, lead guitarist of the band, who uses an Ibanez RG2228 to mix bright chords with very heavy low riffs on the seventh and eighth strings. Of also switched from a seven-string to an eight-string in 2008 and released his signature STEF B-8 with.

In 2008, Ibanez released the Ibanez RG2228-GK, which is the first mass-produced eight-string guitar. 's first album uses a nine-string guitar., guitarist for the group, worked with on a custom mass-produced nine-string guitar. Ten-string [ ]. Main article: Twelve-string electric guitars feature six pairs of strings, usually with each pair tuned to the same note. The extra E, A, D, and G strings add a note one octave above, and the extra B and E strings are in unison.

The pairs of strings are played together as one, so the technique and tuning are the same as a conventional guitar, but they create a much fuller tone, with the additional strings adding a natural. They are used almost solely to play harmony and rhythm parts, rather than for.

They are relatively common in music. Is the folk artist most identified with the twelve-string guitar, usually acoustic with a pickup.

Of the and of the brought the electric twelve-string to notability in. During the Beatles' first trip to the United States, in February 1964, Harrison received a new model guitar from the company, a twelve-string electric made to look onstage like a six-string. He began using the 360 in the studio on Lennon's 'You Can't Do That' and other songs.

McGuinn began using electric twelve-string guitars to create the jangly, ringing sound of the Byrds. Both, the guitarist with, and, a solo artist, are well known as twelve-string guitar players. Third-bridge [ ]. A (or, less commonly, 'twin-neck') guitars enable guitarists to play both guitar and bass guitar or, more commonly, both a six-string and a. In the mid-1960s, one of the first players to use this type of guitar was ' guitarist.

Another early user was. The double-neck guitar was popularized by, who used a custom-made, cherry-finished to perform ', ' and ', although for the recording of 'Stairway to Heaven' he used a Fender Telecaster and a Fender XII electric twelve-string.

Of and is also famous for his use of a double-neck guitar during live shows. Of the used the Gibson EDS-1275 during the tour. Muse guitarist and vocalist uses a silver Manson double-neck on his band's.

Guitarist is also known for using double-neck guitars in the live performance of several songs. In performances of the song 'Xanadu' during the band's 2015 R40 anniversary tour, Lifeson played a white Gibson EDS-1275 double-neck guitar with six-string and twelve-string necks, while bassist performed with a double-neck Rickenbacker guitar with four-string bass and twelve-string guitar necks. Uses [ ] Popular music [ ] typically uses the electric guitar in two roles: as a rhythm guitar to provide the basic and, and a lead guitar that plays lines, melodic, and. In some bands with two guitarists, both may play in tandem, and trade off rhythm and lead roles. In bands with a single guitarist, the guitarist may switch between these roles, playing chords to accompany the singer's lyrics, and a solo. Has been used in many genres, including,,,,,,,,, and In the most commercially available and consumed pop and rock genres, electric guitars tend to dominate their cousins in both the recording studio and live venues, especially in the 'harder' genres such as and.

However the acoustic guitar remains a popular choice in, and especially, and it is widely used in. Even metal and hard rock guitarists play acoustic guitars for some and for acoustic performances. Jazz and other more complex styles [ ] playing styles include rhythm guitar-style ' (accompanying) with jazz chord (and in some cases, ) and 'blowing' (improvising solos) over jazz with jazz-style phrasing and ornaments.

The accompanying style for electric guitar in most styles differs from the way chordal instruments accompany in many popular styles of music. In rock and pop, the rhythm guitarist typically performs chords in dense and regular fashion to define a tune's rhythm. Simpler music tends to use chord voicings focused on the first, third, and fifth notes of the chord.

In contrast, more complex music styles of pop might intermingle periodic chords and delicate voicings into pauses in the melody or solo. Complex guitar chord voicings are often have no, especially in chords that have more than six notes.

Such chords typically emphasize the third and seventh notes of the chord. These chords also often include the 9th, 11th and 13th notes of the chord, which are called extensions, or color notes. When guitarists who play jazz and other more complex styles, they use scales, modes, and arpeggios associated with the chord progression. The must learn how to use scales (whole tone scale, chromatic scale, etc.) to solo over chord progressions. Soloists try to imbue melodic phrasing with the sense of natural breathing and legato phrasing used by players of other instruments. Jazz guitarists are influenced by trumpet, saxophone, and other horn players.

Celtic fingerstyle players are influenced and. Jazz guitarists typically play hollow-body instruments, but also use solid-body guitars. Hollow-body instruments were the first guitars used in jazz in the 1930s and 1940s. During the 1970s era, many jazz guitarists switched to the solid body guitars that dominated the rock world, using powerful guitar amps for volume.

Contemporary classical music [ ]. • Hempstead, Colin; Worthington, William E. Taylor & Francis.

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23 (4): 349.. Sources [ ] • Broadbent, Peter (1997). Charlie Christian: Solo Flight – The Seminal Electric Guitarist. Ashley Mark Publishing Company.. External links [ ] Wikimedia Commons has media related to. • – an exhibit at the Museum of Making Music, National Association of Music Merchants, Carlsbad, CA – some of the earliest electric guitars and their history, from the collection of Lynn Wheelwright and others • Vintage guitar's from America, Japan, and Italy. Pictures, history, and forums.

• – Online exhibition at the 's.