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A musical instrument having a flat-backed rounded body that narrows in the middle, a long fretted neck, and usually six strings, played by strumming or plucking.
[French guitare, from Spanish guitarra, from Greek kitharā, cithara.]
guitarist gui·tar'ist n.Background
A member of the family of musical instruments called chordophones, the guitar is a stringed instrument with which sound is produced by "plucking" a series of strings running along the instrument's body. While the strings are plucked with one hand, they are simultaneously fingered with the other hand against frets, which are metal strips located on the instrument's neck. The subsequent sound is amplified through a resonating body. There are four general categories of acoustic (non-electric) guitars: flat-top steel-stringed, arched top, classic, and flamenco.
References to guitar-like instruments date back many centuries, and virtually every society throughout history has been found to have used a variation of the instrument. The forerunner of today's guitars were single-string bows developed during early human history. In sections of Asia and Africa, bows of this type have been unearthed in archaeological digs of ancient civilizations. Interestingly, one of these discoveries included an ancient Hittite carving—dating back more than 3,000 years—that depicted an instrument bearing many of the same features of today's guitar: the curves of the body, a flat top with an incurred arc of five sound holes on either side, and a long fretted neck that ran the entire length of the body.
As music technology developed, more strings were added to the early guitars. A four-string variety (named guitarra latina) existed in Spain in the late thirteenth century. The guitarra latina closely resembled the ancient Hittite carving except that the instrument now included a bridge that held the strings as they passed over the soundhole. When a fifth string was added in the early sixteenth century, the guitar's popularity exploded. A sixth string (bass E) was added near the end of 1700s, an evolution that brought the instrument closer to its present day functioning. The Carulli guitar of 1810 was one of the first to have six single strings tuned to notes in the present arrangement: E A D G B E.
Guitar technology finally made its way to the United States in the early nineteenth century, with Charles Friedrich Martin, a German guitar maker who emigrated to New York in 1833, leading the way. In the early 1900s, the Martin Company—now located in Nazareth, Pennsylvania—produced larger guitars that still adhered to the design of the classic models, especially the Spanish guitar. Another company, the Gibson company, followed suit and began to produce large steel-string guitars with arched fronts and backs. Known as the cello guitar, this brand of instrument produced a sound more suited for jazz and dance clubs. Another major innovation of the early 1900s was the use of magnetic pickups fitted beneath the strings by which sound traveled through a wire into an amplifier. These instruments would later evolve into electric guitars.
Raw Materials
The guitar industry is in virtual agreement on the woods used for the various parts of the instrument. The back and sides of the guitar's body are usually built with East Indian or Brazilian rosewood. Historically, Brazilian rosewood has been the choice of connoisseurs. However, in an attempt to preserve the wood's dwindling supply, the Brazilian government has placed restrictions on its export, thus raising the price and making East Indian rosewood the current wood of choice. Less expensive brands use mahogany or maple, but the sound quality suffers in guitars constructed with those types of wood.
The top (or soundboard) of the guitar is traditionally constructed of Alpine spruce, although American Sika spruce has become popular among U.S. manufacturers. Cedar and redwood are often substituted for spruce, although these woods are soft and easily damaged during construction.
The neck, which must resist distortion by the pull of the strings and changes in temperature and humidity, is constructed from mahogany and joins the body between the fourteenth and twelfth frets. Ideally, the fingerboard is made of ebony, but rosewood is often used as a less expensive alternative. Most modern guitars use strings made of some type of metal (usually steel).
The Manufacturing
Process
The first and most important step in guitar construction is wood selection. The choice of wood will directly affect the sound quality of the finished product. The wood must be free of flaws and have a straight, vertical grain. Since each section of the guitar uses different types of woods, the construction process varies from section to section. Following is a description of the manufacture of a typical acoustic guitar.
Bookmatching
Strutting
Constructing the sides
Neck and fingerboard
Bridge and saddle
Tuning machine
Electric Guitars
A separate but closely related group of guitars is the electric guitar, which uses a device known as a pickup—a magnet surrounded by wire—to convert the energy from string vibrations into an electrical signal. The signal is sent to an amplifier, where it is boosted thousands of times. The body of an electric guitar has little impact on the quality of sound produced, as the amplifier controls both the quality and loudness of the sound. Acoustic guitars can also be fitted with electric pickups, and there are some models available today that already have the pickup built into the body.
Quality Control
Most guitar manufacturers are small, highly personal companies that stress detail and quality. Each company does its own research and testing, which virtually insure the customer of a flawless guitar. During the past few decades, the guitar industry has become more mechanized, allowing for greater speed, higher consistency and lower pricing. Although purists resist mechanization, a well-trained workman using machine tools can usually produce a higher-quality instrument than a craftsman working alone. The final testing procedures at most manufactures are quite stringent; only the best guitars leave the plant, and more than one person makes the final determination as to which instruments are shipped out and which are rejected.
Where To Learn More
Books
Cumpiano, William R. Guitarmaking: Tradition & Technology. Rosewood Press, 1987.
Evans, Tom and Mary Anne. Guitars: Music, History, Construction and Players from the Renaissance to Rock. Facts on File, 1977.
Hill, Thomas. The Guitar: An Introduction to the Instrument. Watts Publishing, 1973.
How It Works: The Illustrated Science and Invention Encyclopedia. Vol. 9. H. S. Stuttman, 1983.
Kamimoto, Hideo. Complete Guitar Repair. Oak Publications, 1975.
Wheeler, Thomas. The Guitar Book. Harper & Row, 1974.
Periodicals
Del Ray, Tiesco. "Off the Wall: The Theory of Reverse Ergonomics," Guitar Player. March, 1986, p. 102.
Sievert, Jon. "Steinberger Factory Tour," Guitar Player. December, 1988, p. 38.
Smith, Richard. "Inside Rickenbacker: New Factory, Old Traditions," Guitar Player. February, 1990, p. 61.
Widders-Ellis, Andy. "Tomorrow's Acoustics: The Dawning of a New Golden Age," Guitar Player. April, 1992, p. 43.
[Article by: Jim Acton]
A string instrument of the lute family. The modern classical guitar has a fretted fingerboard (usually with 19 frets), six strings, a wooden resonator with a waisted figure-of-eight shape, a circular soundhole and a flat back (for illustration, see Lute). A rosewood bridge acts as a stringholder. The strings are nylon (the three lower overspun with fine metal), tuned by rear pegs activating a geared mechanism. The standard tuning is E-A-d-g-b-e′; guitar music is notated an octave higher than it sounds.
It is not known whether the guitar was introduced to medieval Europe by the Arabs or was an indigenous European instrument. Names related to ‘guitar’ occur in medieval literature from the 13th century but may refer to such instruments as the gittern. Its history in Europe can be traced back to the Renaissance; during the 15th century a four-course guitar appeared, having much in common with the lute and vihuela.
16th-century guitars were much smaller than modern ones; their gut strings (the three lower ones doubled) were tuned to a pattern of 4th-major 3rd-4th (e.g. g/g′-c′/c′-e′/e′-a′). In polyphonic music, technique was similar to that of the lute and vihuela, with the right-hand little finger resting on the bridge or soundtable, while the thumb and first two fingers plucked the strings. Music, notated in Tablature, included simple dances, chansons and fantasias. The four-course guitar continued in use in the 17th and 18th centuries, mainly in popular music, and survives in Spanish and Portuguese cultures as a small treble guitar.
Five-course guitars, often called ‘viola’ or ‘viola da mano’, were played from the late 15th century, especially in Italy. They were typically tuned a/a-d′/d′-g/g-b/b-e′ (with the third course at the lowest pitch), though some had a lower octave (bourdon) on some courses (e.g. A/a-d/d′-g/g-b/b-e′). Guitar music called for strumming, plucking individual strings and other techniques.
In the mid-18th century a special type of guitar, the chitarra battente, developed, probably for accompanying popular music. It had a deeply vaulted back and metal strings and frets; the strings, passing over a movable bridge, were fixed at the bottom of the body and probably played with a plectrum.
Baroque guitars are richly decorated. During the 17th century many tutors were published, often containing solos and dance suites and many in an alphabetical system of notating left-hand chords. A huge repertory of Italian arias with guitar accompaniment was published.
In the late 18th century, first in France, guitar tablature was replaced by staff notation, single strings were used in place of double courses and a sixth string was added. In the early 19th other changes established the form that developed into the modern guitar. Machine heads replaced wooden pegs, fixed frets (of ivory or ebony, then metal) were used instead of gut, and a flat back became standard. Some players rested the right hand on the table, some used fingernails. The instrument was held in various ways.
Fernando Sor, a Spaniard who moved to Paris (a centre of interest in the guitar), and the Italian Mauro Giuliani were among the most influential guitarist-composers, establishing a repertory of large-scale works (including concertos and chamber music) as well as easy pieces and studies, characterized by their elegance and vivacity. With the Spanish maker Antonio de Torres Jurado (1817-92), the guitar achieved a standard size and form. He made it larger and established the vibrating length of the strings at 65 cm he developed fan-strutting of the soundboard and introduced the modern bridge. The instrument is now rested on the left thigh but right-hand position and technique varies.
In the early 20th century the guitar lacked a repertory to give it a status comparable with other instruments. Works were transcribed from other media (e.g. music for lute and vihuela, other string instruments and keyboard). The Spanish guitarist Andrés Segovia was influential in making it a respected concert instrument; he made many transcriptions and inspired composers to write for him. Falla (Homenaje pour le tombeau de Claude Debussy), Rodrigo (Concierto de Aranjuez), Castelnuovo-Tedesco, Manuel Ponce, Villa-Lobos (Douze études, Cinq préludes), Britten and Gerhard are among those who have written for the guitar. The 20th-century repertory has introduced new techniques and sonorities, sometimes derived from folk music, flamenco and jazz.
Variants include the Lyre guitar, guitars with extra strings and instruments that varied in size and hence in pitch. Of 20th-century variants, the flamenco guitar is closest to the classical, but lighter. Guitarists playing in jazz, blues, folk etc have required instruments with greater volume and penetration such as the ‘Dreadnought’ (larger and broader than the normal guitar), acoustic guitars and, most recently, the
For more information on guitar, visit Britannica.com.
From our Archives: Today's Highlights, February 21, 2005
Bibliography
See H. Turnbull, The Guitar from the Renaissance to the Present (1974); J. Tyler, The Early Guitar (1980); T. Wheeler, American Guitars (1982).
A stringed musical instrument (see strings) usually played by strumming or plucking. Guitars are widely used in folk music and, often amplified electronically, in country and western music and rock 'n' roll.
In rejecting the Beatles, 1962: We don't like their sound, and guitar music is on the way out.
— Decca Recording Co.
The guitar is a musical instrument with ancient roots that is used in a wide variety of musical styles. It typically has six strings, but four, seven, eight, ten, and twelve string guitars also exist.
Guitars are recognized as one of the primary instruments in blues, country, flamenco, rock music, and many forms of pop. There is also a solo classical instrument. Guitars may be played acoustically, where the tone is produced by vibration of the strings and modulated by the hollow body, or they may rely on an amplifier that can electronically manipulate tone. Such electric guitars were introduced in the 20th century and continue to have a profound influence on popular culture.
Traditionally guitars have usually been constructed of combinations of various woods and strung with animal gut, or more recently, with either nylon or steel strings. Guitars are made and repaired by luthiers.
Before the development of the electric guitar and the use of synthetic materials, a guitar was defined as being an instrument having "a long, fretted neck, flat wooden soundboard, ribs, and a flat back, most often with incurved sides".[1] Instruments similar to the guitar have been popular for at least 5,000 years. The guitar appears to be derived from earlier instruments known in ancient India and Central Asia as the Sitara. The oldest known iconographic representation of an instrument displaying all the essential features of a guitar being played is a 3300 year old stone carving of a Hittite bard.[2] The modern word, guitar, was adopted into English from Spanish guitarra, derived from the Latin word cithara, which in turn was derived from the earlier Greek word kithara, which perhaps derives from Persian sihtar[3]. Sihtar itself is related to the Indian instrument, the sitar.
The modern guitar is descended from the Roman cithara brought by the Romans to Hispania around 40 AD, and further adapted and developed with the arrival of the four-string oud, brought by the Moors after their invasion of the Iberian peninsula during the 8th century AD.[4] Elsewhere in Europe, the indigenous six-string Scandinavian lut (lute), had gained in popularity in areas of Viking incursions across the continent. Often depicted in carvings c.800 AD, the Norse hero Gunther (also known as Gunnar), played a lute with his toes as he lay dying in a snake-pit, in the legend of Siegfried.[5] By 1200 AD, the four string "guitar" had evolved into two types: the guitarra morisca (Moorish guitar) which had a rounded back, wide fingerboard and several soundholes, and the guitarra latina (Latin guitar) which resembled the modern guitar with one soundhole and a narrower neck.[6]
The Spanish vihuela or "viola da mano", a guitar-like instrument of the 16th century, appears to be an aberration in the transition from the renaissance instrument to the modern guitar. It had lute-style tuning and a guitar-like body. Its construction had as much in common with the modern guitar as with its contemporary four-course renaissance guitar. The vihuela enjoyed only a short period of popularity; the last surviving publication of music for the instrument appeared in 1576. It is not clear whether it represented a transitional form or was simply a design that combined features of the Arabic oud and the European lute. In favor of the latter view, the reshaping of the vihuela into a guitar-like form can be seen as a strategy of differentiating the European lute visually from the Moorish oud.
The Vinaccia family of luthiers is known for developing the mandolin, and may have built the earliest extant six string guitar. Gaetano Vinaccia (1759 - after 1831)[7] has his signature on the label of a guitar built in Naples, Italy for six strings with the date of 1779.[8][9] This guitar has been examined and does not show tall-tale signs of modifications from a double-course guitar although fakes are known to exist of guitars and identifying labels from that period.
Modern dimensions of the classical instrument were established by Antonio Torres Jurado (1817-1892), working in Seville in the 1850s. Torres and Louis Panormo of London (active 1820s-1840s) were both responsible for demonstrating the superiority of fan strutting over transverse table bracing.[10]
The electric guitar was patented by George Beauchamp in 1936. Beauchamp co-founded Rickenbacher which used the horseshoe-magnet pickup. However, it was Danelectro that first produced electric guitars for the wider public.
Guitars can be divided into two broad categories, acoustic and electric:
An acoustic guitar is one not dependent on an external device to be heard. The acoustic guitar is quieter than other instruments commonly found in bands and orchestras so when playing within such groups it is often externally amplified. Many acoustic guitars available today feature a variety of pickups which enable the player to amplify and modify the raw guitar sound.
There are several notable subcategories within the acoustic guitar group: classical and flamenco guitars; steel string guitars, which include the flat top or "folk" guitar; twelve string guitars and the arch top guitar. The acoustic guitar group also includes unamplified guitars designed to play in different registers such as the acoustic bass guitar which has a similar tuning to that of the electric bass guitar.
Resonator guitars may have either one resonator cone or three resonator cones. Three-cone resonators have two cones on the left above one another and one cone immediately to the right. The method of transmitting sound resonance to the cone is either a "biscuit" bridge, made of a small piece of hardwood, or a "spider" bridge, made of metal and larger in size. Three-cone resonators always use a specialized metal spider bridge.
The type of resonator guitar with a neck with a square cross-section -- called "square neck" -- is usually played face up, on the lap of the seated player, and often with a metal or glass slide. The round neck resonator guitars are normally played in the same fashion as other guitars, although slides are also often used, especially in blues.
Electric guitars can have solid, semi-hollow, or hollow bodies, and produce little sound without amplification. Electromagnetic pickups convert the vibration of the steel strings into electrical signals which are fed to an amplifier through a cable or radio transmitter. The sound is frequently modified by other electronic devices or the natural distortion of valves (vacuum tubes) in the amplifier. There are two main types of pickup: single coil and double coil (known as humbuckers), each of which can be passive or active. The electric guitar is used extensively in jazz, blues and rock and roll, and was commercialized by Gibson together with Les Paul and independently by Leo Fender of Fender Music. The lower fretboard action (the height of the strings from the fingerboard) and its electrical amplification lend the electric guitar to some techniques which are less frequently used on acoustic guitars. These techniques include tapping, extensive use of legato through pull-offs and hammer-ons (also known as slurs), pinch harmonics, volume swells and use of a tremolo arm or effects pedals.
Seven-string solid body electric guitars were popularized in the 1980s and 1990s in part due to the release of the Ibanez Universe guitar, endorsed by Steve Vai. Other artists go a step further, by using an 8 string guitar with two extra low strings. Although the most common 7 string has a low B string, Roger McGuinn (Of Byrds/Rickenbacker Fame) uses an octave G string paired with the regular G string as on a 12 string guitar, allowing him to incorporate chiming 12 string elements in standard 6 string playing.
The electric bass guitar is similar in tuning to the traditional double bass viol. Hybrids of acoustic and electric guitars are also common. There are also more exotic varieties, such as guitars with two, three[11] or rarely four necks, all manner of alternate string arrangements, fretless fingerboards (used almost exclusively on bass guitars, meant to emulate the sound of a stand-up bass), 5.1 surround guitar, and such.
Some electric guitar and electric bass guitar models feature Piezoelectric pickups, which function as transducers to provide a sound closer to that of an acoustic guitar with the flip of a switch or knob, rather than switching guitars.
Guitars can be constructed to meet the demands of both left and right-handed players. Traditionally the dominant hand is assigned the task of plucking or strumming the strings. For the majority of people this entails using the right hand. This is because musical expression (dynamics, tonal expression and colour etc) is largely determined by the plucking hand, whilst the fretting hand is assigned the lesser mechanical task of depressing and gripping the strings. This is similar to the convention of the violin family of instruments where the right hand controls the bow. A minority, however, believe that left-handed people should learn to play guitars strung in the manner used by right-handed people, simply to standardise the instrument.
The headstock is located at the end of the guitar neck furthest from the body. It is fitted with machine heads that adjust the tension of the strings, which in turn affects the pitch. Traditional tuner layout is "3+3" in which each side of the headstock has three tuners (such as on Gibson Les Pauls). In this layout, the headstocks are commonly symmetrical. Many guitars feature other layouts as well, including six-in-line (featured on Fender Stratocasters) tuners or even "4+2" (Ernie Ball Music Man). However, some guitars (such as Steinbergers) do not have headstocks at all, in which case the tuning machines are located elsewhere, either on the body or the bridge.
The nut is a small strip of bone, plastic, brass, corian, graphite, stainless steel, or other medium-hard material, at the joint where the headstock meets the fretboard. Its grooves guide the strings onto the fretboard, giving consistent lateral string placement. It is one of the endpoints of the strings' vibrating length. It must be accurately cut, or it can contribute to tuning problems due to string slippage, and/or string buzz.
Also called the fingerboard, the fretboard is a piece of wood embedded with metal frets that comprises the top of the neck. It is flat on classical guitars and slightly curved crosswise on acoustic and electric guitars. The curvature of the fretboard is measured by the fretboard radius, which is the radius of a hypothetical circle of which the fretboard's surface constitutes a segment. The smaller the fretboard radius, the more noticeably curved the fretboard is. Most modern guitars feature a 12" neck radius, while older guitars from the '60's and '70's usually feature a 6" - 8" neck radius. Pinching a string against the fretboard effectively shortens the vibrating length of the string, producing a higher pitch. Fretboards are most commonly made of rosewood, ebony, maple, and sometimes manufactured or composite materials such as HPL or resin. See below on section 'Neck" for the importance of the length of the fretboard in connection to other dimensions of the guitar.
Frets are metal strips (usually nickel alloy or stainless steel) embedded along the fretboard and located at exact points that divide the scale length in accordance with a specific mathematical formula. Pressing a string against a fret determines the strings' vibrating length and therefore its resultant pitch. The pitch of each consecutive fret is defined at a half-step interval on the chromatic scale. Frets worn down from heavy use can be replaced or, to a certain extent, re-shaped as required. Frets are available in different gauges.
Frets are laid out to a mathematical ratio that results in equal tempered division
of the octave. The ratio of the spacing of two consecutive frets is the twelfth root of two ![\sqrt[12]{2}](http://content.answers.com/main/content/wp/en/math/7/0/b/70b8b8fc763c20423a65bd934e378085.png)
, whose numeric value is about 1.059463.
The twelfth fret divides the scale length in two exact halves and the 24th
fret position divides the scale length in half yet again. Every twelve frets
represents one octave. In practise, luthiers determine fret positions using the constant 17.817,
which is derived from the twelfth root of two. The scale length divided by this value yields the distance from the nut to the first fret. That
distance is subtracted from the scale length and the result is divided in two
sections by the constant to yield the distance from the first fret to the second fret. Positions for the remainder of the frets
are calculated in like manner.[12]
There are several different fret gauges, which can be fitted according to player preference. Among these are "jumbo" frets, which have much thicker gauge, allowing for use of a slight vibrato technique from pushing the string down harder and softer. "Scalloped" fretboards, where the wood of the fretboard itself is "scooped out" between the frets allows a dramatic vibrato effect. Fine frets, much flatter, allow a very low string-action but require other conditions such as curvature of the neck to be well maintained in order to prevent buzz.
The truss rod is a metal rod that runs along the inside of the neck. It is used to correct changes to the neck's curvature caused by the neck timbers aging, changes in humidity or to compensate for changes in the tension of strings. The tension of the rod and neck assembly is adjusted by a hex nut or an allen-key bolt on the rod, usually located either at the headstock, sometimes under a cover, or just inside the body of the guitar underneath the fretboard and accessible through the sound hole. Some truss rods can only be accessed by removing the neck. The truss rod counteracts the immense amount of tension the strings place on the neck, bringing the neck back to a straighter position. Turning the truss rod clockwise will tighten it, counteracting the tension of the strings and straightening the neck or creating a backward bow. Turning the truss rod counter-clockwise will loosen it, allowing string tension to act on the neck and creating a forward bow. Adjusting the truss rod affects the intonation of a guitar as well as the height of the strings from the fingerboard, called the action. Some truss rod systems, called "double action" truss systems, tighten both ways, allowing the neck to be pushed both forward and backward (standard truss rods can only be released to a point beyond which the neck will no longer be compressed and pulled backward). Classical guitars do not require truss rods as their nylon strings exert a lower tensile force with lesser potential to cause structural problems.
Inlays are visual elements set into the exterior surface of a guitar. The typical locations for inlay are on the fretboard,
headstock, and on acoustic guitars around the soundhole, known as the
Fretboard inlays are most commonly shaped like dots, diamond shapes, parallelograms, or large blocks in between the frets. Dots are usually inlaid into the upper edge of the fretboard in the same positions, small enough to be visible only to the player. Some older or high-end instruments have inlays made of mother of pearl, abalone, ivory, coloured wood or other exotic materials and designs. Simpler inlays are often made of plastic or painted. High-end classical guitars seldom have fretboard inlays as a well trained player is expected to know his or her way around the instrument.
In addition to fretboard inlay, the headstock and soundhole surround are also frequently inlaid. The manufacturer's logo or a small design is often inlaid into the headstock. Rosette designs vary from simple concentric circles to delicate fretwork mimicing the historic rosette of lutes. Bindings that edge the finger and sound boards are sometimes inlaid. Some instruments have a filler strip running down the length and behind the neck, used for strength and/or to fill the cavity through which the trussrod was installed in the neck.
Elaborate inlays are a decorative feature of many limited edition, high-end and custom-made guitars. Guitar manufacturers often release such guitars to celebrate significant or historic milestones.
A guitar's frets, fretboard, tuners, headstock, and truss rod, all attached to a long wooden extension, collectively constitute its neck. The wood used to make the fretboard will usually differ from the wood in the rest of the neck. The bending stress on the neck is considerable, particularly when heavier gauge strings are used (see Strings and tuning), and the ability of the neck to resist bending (see Truss rod) is important to the guitar's ability to hold a constant pitch during tuning or when strings are fretted. The rigidity of the neck with respect to the body of the guitar is one determinant of a good instrument versus a poor one. The shape of the neck can also vary, from a gentle "C" curve to a more pronounced "V" curve. There are many different types of neck profiles available, giving the guitarist many options. Some aspects to consider in a guitar neck may be the overall width of the fingerboard, scale (distance between the frets), the neck wood, the type of neck construction (for example, the neck may be glued in or bolted on), and the shape (profile) of the back of the neck. Other type of material used to make guitar necks are graphite (Steinberger guitars), aluminium (Kramer Guitars, Travis Bean and Veleno guitars), or carbon fiber (Modulus Guitars and ThreeGuitars).
This is the point at which the neck is either bolted or glued to the body of the guitar. Almost all acoustic guitars, with the primary exception of Taylors, have glued (otherwise known as set) necks, while electric guitars are constructed using both types.
Commonly used set neck joints include mortise and tenon joints (such as those used by CF Martin & Co. guitars), dovetail joints (also used by CF Martin on the D28 and similar models) and Spanish heel neck joints which are named after the shoe they resemble and commonly found in classical guitars. All three types offer stability. Bolt-on necks, though they are historically associated with cheaper instruments, do offer greater flexibility in the guitar's set-up, and allow easier access for neck joint maintenance and repairs.
Another type of neck, only available for solid body electric guitars, is the neck-through-body construction. These are designed so that everything from the machine heads down to the bridge are located on the same piece of wood. The sides (also known as wings) of the guitar are then glued to this central piece. Some luthiers prefer this method of construction as they claim it allows better sustain of each note. Some instruments may not have a neck joint at all, having the neck and sides built as one piece and the body built around it.
Modern guitar strings are manufactured in either metal or organo-carbon material. Instruments utilising "steel" strings may have strings made of alloys incorporating steel, nickel or phosphor bronze. Classical and flamenco instruments have historically used gut strings but these have been superseded by nylon and carbon-fibre materials. Bass strings for both instruments are wound rather than monofilament.
Guitar strings are strung almost parallel to the neck, whose surface is covered by the fingerboard (fretboard). By depressing a string against the fingerboard, the effective length of the string can be changed, which in turn changes the frequency at which the string will vibrate when plucked. Guitarists typically use one hand to pluck the strings and the other to depress the strings against the fretboard.
The strings may be plucked using either the fingers or a pick (or plectrum).
In acoustic guitars, string vibration is transmitted through the bridge and saddle to the body via sound board. The sound board is typically made of tone woods such as spruce or cedar. Timbers for tone woods are chosen for both strength and ability to transfer mechanical energy from the strings to the air within the guitar body. Sound which is further shaped by the characteristics of the guitar body's resonant cavity.
In electric guitars, transducers known as pickups convert string vibration to an electric signal, which in turn is amplified and fed to speakers, which vibrate the air to produce the sound we hear. Nevertheless, the body of the electric guitar body still performs a role in shaping the resultant tonal signature.
In an acoustic instrument, the body of th guitar is a major determinant of the overall sound quality. The guitar top, or soundboard, is a finely crafted and engineered element made of tonewoods such as spruce and red cedar. This thin piece of wood, often only 2 or 3mm thick, is strengthened by differing types of internal bracing. The top is considered by many luthiers to be the dominant factor in determining the sound quality. The majority of the instrument's sound is heard through the vibration of the guitar top as the energy of the vibrating strings is transferred to it.
Body size, shape and style has changed over time. 19th century guitars, now known as salon guitars, were smaller than modern instruments. Differing patterns of internal bracing have been used over time by luthiers. Torres, Hauser, Ramirez, Fleta, and C.F. Martin were among the most influential designers of their time. Bracing not only strengthens the top against potential collapse due to the stress exerted by the tensioned strings, but also affects the resonance characteristics of the top. The back and sides are made out of a variety of timbers such as mahogany, Indian rosewood and highly regarded Brazilian rosewood (Dalbergia nigra). Each one is primarily chosen for their aesthetic effect and can be decorated with inlays and purfling.
The body of an acoustic guitar has a sound hole through which sound is projected. The sound hole is usually a round hole in the top of the guitar under the strings. Air inside the body vibrates as the guitar top and body is vibrated by the strings, and the response of the air cavity at different frequencies is characterised, like the rest of the guitar body, by a number of resonance modes at which it responds more strongly.
Instruments with larger areas for the guitar top were introduced by Martin in an attempt to create louder volume levels. The popularity of the larger "dreadnought" body size amongst acoustic performers is related to the greater sound volume produced.
Most electric guitar bodies are made of wood and include a plastic pick guard. Boards wide enough to use as a solid body are very expensive due to the worldwide depletion of hardwood stock since the 70's, so the wood is rarely one solid piece. Most bodies are made of two pieces of wood with some of them including a seam running down the centre line of the body. The most common woods used for electric guitar body construction include maple, basswood, ash, poplar, alder, and mahogany. Many bodies will consist of good sounding but inexpensive woods, like ash, with a "top", or thin layer of another, more attractive wood (such as maple with a natural "flame" pattern) glued to the top of the basic wood. Guitars constructed like this are often called "flame tops". The body is usually carved or routed to accept the other elements, such as the bridge, pickup, neck, and other electronic components. Most electrics have a polyurethane or nitrocellulose lacquer finish. Other alternative materials to wood, are used in guitar body construction. Some of these include carbon composites, plastic material (such as polycarbonate) and aluminium alloys.
Pickups are transducers attached to a guitar that detect (or "pick up") string vibrations and convert the mechanical energy of the string into electrical energy. The resultant electrical signal can then be electronically amplified. The most common type of pickup is electromagnetic in design. These contain magnets that are tightly wrapped in a coil, or coils, of copper wire. Such pickups are usually placed right underneath the guitar strings. Electromagnetic pickups work on the same principles and in a similar manner to an electrical generator. The vibration of the strings causes a small voltage to be created in the coils surrounding the magnets, this signal voltage is later amplified.
Traditional electromagnetic pickups are either single-coil or double-coil. Single coil pickups are susceptable to noise induced from electric fields, usually mains-frequency (60 or 50 hertz) hum. The introduction of the double-coil humbucker in the mid 50's did away with this problem through the use of two coils, one of which is wired in a reverse polarity orientation.
The type and model of pickups used can greatly affect the tone of the guitar. Typically, humbuckers, which are two magnet/coil assemblies attached to each other are traditionally associated a heavier sound. Single coil pickups, one magnet wrapped in copper wire, are used by guitarists seeking a brighter, twangier sound with greater dynamic range.
Modern pickups are tailored to the sound desired. A commonly applied approximation used in selection of pickup is that less wire (lower dc resistance) = brighter sound, more wire = "fat" tone. Other options include specialized switching that produces coil-splitting, in/out of phase and other effects. Guitar circuits are either active, needing a battery to power their circuit, or, as in most cases, equipped with a passive circuit.
Fender Stratocaster type guitars generally utilize 3 single coil pickups, while most Gibson Les Paul types use humbucker pickups.
Piezoelectric, or piezo, pickups represent another class of pickup. These employ piezoelectricity to generate the musical signal and are popular in hybrid electro-acoustic guitars. A crystal is located under each string, usually in the saddle. When the string vibrates, the shape of the crystal is distorted, and the stresses associated with this change produce tiny voltages across the crystal that can be amplified and manipulated.
Some piezo equipped guitars use what is known as a hexaphonic pickup. "Hex" is a prefix meaning six. In a hexaphonic pickup separate outputs are obtained from discrete piezoelectric pickups for each of the six strings. This arrangement allows the signal to be easily modified by on-board modelling electronics, as in the Line 6 Variax brand of electric guitars, the guitars allow for a variety of different sounds to be obtained by digitally manipulating the signal. This allows a guitar to mimic many vintage models of guitar, as well as output alternate tunings without the need to adjust the strings.
Another use for hexaphonic pickups is to send the output signals to a MIDI interpretation device, which determines the note pitch, duration, attack and decay characteristics and so forth. The MIDI (Musical Instrument Digital Interface) interpreter then sends the note information to a sound bank device. The resulting sound can closely mimic numerous types of instrument.
On guitars that have them, these components and the wires that connect them allow the player to control some aspects of the sound like volume or tone. These at their simplest consist of passive components such as potentiometers and capacitors, but may also include specialized integrated circuits or other active components requiring batteries for power, for preamplification and signal processing, or even for assistance in tuning. In many cases the electronics have some sort of shielding to prevent pickup of external interference and noise.
The top, back and ribs of an acoustic guitar body are very thin (1-2 mm), so a flexible piece of wood called lining is glued into the corners where the rib meets the top and back. This interior reinforcement provides 5 to 20 mm of solid gluing area for these corner joints. Solid linings are often used in classical guitars, while kerfed lining is most often found in steel string acoustics. Kerfed lining is also called kerfing (because it is scored, or kerfed to allow it to bend with the shape of the rib).
During final construction, a small section of the outside corners is carved or routed out and then filled with binding material on the outside corners and decorative strips of material next to the binding, which are called purfling. This binding serves to seal off the endgrain of the top and back. Purfling can also appear on the back of an acoustic guitar, marking the edge joints of the two or three sections of the back.
Binding and purfling materials are generally made of either wood or plastic.
The main purpose of the bridge on an acoustic guitar is to transfer the vibration from the strings to the soundboard, which vibrates the air inside of the guitar, thereby amplifying the sound produced by the strings.
On both electric and acoustic
