Parts of the guitar
Headstock
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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.
Nut
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.
Fretboard
Also called the fingerboard in fretless guitars and basses, 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.
Frets
Frets are metal strips (usually nickel alloy or stainless steel) embedded along the fretboard which are placed in points along the length of string that divide it mathematically. When strings are pressed down behind them, frets shorten the strings' vibrating lengths to produce different pitches- each one is spaced a half-step apart on the 12 tone scale. For more on fret spacing, see the Strings and Tuning section below. Frets are usually the first permanent part to wear out on a heavily played electric guitar. They can be re-shaped to a certain extent and can be replaced as needed. Frets also indicate fractions of the length of a string (the string midpoint is at the 12th fret; one-third the length of the string reaches from the nut to the 7th fret, the 7th fret to the 19th, and the 19th to the saddle; one-quarter reaches from nut to fifth to twelfth to twenty-fourth to saddle). This feature is important in playing harmonics. Frets are available in several different gauges, depending on the type of guitar and the player's style.
Guitars have frets on the fingerboard to fix the positions of notes and scales, which gives them equal temperament. Consequently, the ratio of the spacing of two consecutive frets is the twelfth root of two ![\sqrt[12]{2}](http://upload.wikimedia.org/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 (if present) divides the scale length in half yet again. Every twelve frets represents one octave. In practice, luthiers determine fret positions using the constant 17.817152, 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.[5]
There are several styles of fret, which allow different sounds and techniques to be exploited by the player. Among these are "jumbo" frets, which have much thicker wires, allowing for a lighter touch and a slight vibrato technique simply from pushing the string down harder and softer, "scalloped" fretboards, where the wood of the fretboard itself is "scooped out", becoming deeper away from the headstock, which allows a dramatic vibrato effect and other unusual techniques, and fine frets, much flatter, which allow a very low string-action for extremely fast playing, but require other conditions (such as curvature of the neck) to be kept in perfect order to prevent buzz.
Truss rod
The truss rod is a metal rod that runs along the inside of the neck. Its tension is adjusted by a hex nut or an allen-key bolt usually located either at the headstock (sometimes under a cover) or just inside the body of the guitar, underneath the fretboard (accessible through the sound hole). Some truss rods can only be accessed by removing the neck, forcing the luthier to replace it after every adjustment to check its accuracy. The truss rod counteracts the immense amount of tension the strings place on the neck, bringing the neck back to a straighter position. The truss rod can be adjusted to compensate for changes in the neck wood due to changes in humidity or to compensate for changes in the tension of strings. Tightening the rod will curve the neck back and loosening it will return it forward. Adjusting the truss rod affects the intonation of a guitar as well as affecting the action (the height of the strings from the fingerboard). Some truss rod systems, called "double action" truss systems, will tighten both ways, allowing the neck to be pushed both forward and backward (most truss rods can only be loosened so much, beyond which the bolt will just come loose and the neck will no longer be pulled backward). Most classical guitars do not have truss rods, as the nylon strings do not put enough tension on the neck for one to be needed.
Inlays
Inlays are visual elements set into the exterior frame of a guitar. The typical locations for inlay are on the fretboard, headstock, and around the soundhole (called a rosette on acoustic guitars). Inlays range from simple plastic dots on the fretboard to fantastic works of art covering the entire exterior surface of a guitar (front and back). Some guitar players put LEDs in the fretboard as inlays to produce a unique lighting effect onstage. Both Sam Rivers- bassist of rock group Limp Bizkit- and guitar virtuoso Steve Vai have used LEDs as fret inlays.
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 manufacturers go beyond these simple shapes and use more creative designs such as lightning bolts or letters and numbers. The simpler inlays are often done in plastic on guitars of recent vintage, but many older, and newer, high-end instruments have inlays made of mother of pearl, abalone, ivory, coloured wood or any number of exotic materials. On some low-end guitars, they are just painted. Most high-end classical guitars have no inlays at all since a well trained player is expected to know his or her way around the instrument, however players will sometimes make indicators with a marker pen, correction fluid, or a small piece of tape.
The most popular fretboard inlay scheme involves single inlays on the 3rd, 5th, 7th, 9th, 15th, 17th, 19th, and 21st frets, and double inlays on the 12th, sometimes 7th, and (if present) 24th fret. Advantages of such scheme include its symmetry about the 12th fret and symmetry of every half (0-12 and 12-24) about the 7th and 19th frets. However, playing these frets, for example, on E string would yield notes E, G, A, B, C# that barely makes a complete musical mode by themselves.
A less popular fretboard inlay scheme involves inlays on 3rd, 5th, 7th, 10th, 12th, 15th, 17th, 19th, 22nd and 24th frets. Playing these frets, for example, on E string yields notes E, G, A, B, D that fit perfectly into E minor pentatonic. Such a scheme is very close to piano keys colouring (which involves black colouring for sharps that pentatonic consists of) and of some use on classic guitars.
Beyond the fretboard inlay, the headstock and soundhole are also commonly inlaid. The manufacturer's logo is commonly inlaid into the headstock. Sometimes a small design such as a bird or other character or an abstract shape also accompanies the logo. The soundhole designs found on acoustic guitars vary from simple concentric circles to delicate fretwork (referred to as a Rosette). Many high-end guitars have more elaborate decorative inlay schemes. Often the edges of the guitar around the neck and body and down the middle of the back are inlaid. The fretboard commonly has a large inlay running across several frets or the entire length of the fretboard, such as a long vine creeping across the fretboard. Most acoustic guitars have an inlay that borders the sides of the fretboard, and some electrics (namely Fender Stratocasters) have what looks like a wood inlay running on the back of the neck, from about the body to the middle of the neck, commonly referred to as a skunk stripe. In fact this is a filler strip, used to fill the cavity through which the trussrod was installed in the neck.
Some very limited edition high-end or custom-made guitars have artistic inlay designs that span the entire front (or even the back) of the guitar. These designs use a variety of different materials and are created using techniques borrowed from furniture making. While these designs are often just very elaborate decorations, they are sometimes works of art that even depict a particular theme or a scene. Although these guitars are often constructed from the most exclusive materials, they are generally considered to be collector's items and not intended to be played. Large guitar manufacturers often issue these guitars to celebrate a significant historical milestone.
Neck
A guitar's frets, fretboard, tuners, headstock, and truss rod, all attached to a long wooden extension, collectively comprise 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 that 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.
Neck joint or 'Heel'
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 and sustain. 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 it is said to allow 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.
Strings
Guitar strings are strung 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.
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 "conventional" guitars strung in the manner used by right-handed people, simply to standardise the instrument.
The strings may be plucked using either fingers or a plectrum (Guitar pick).The sound of the guitar is achieved either mechanically or electronically, forming two main categories of guitar: acoustic (mechanical amplification) and electric (electronic amplification).
- In acoustic guitars, string vibration is transmitted through the bridge and saddle to the sound board. The sound board, typically made of a light springy wood such as spruce, vibrates the air, producing sound which is further shaped by the guitar body's resonant cavity.
Body (acoustic guitar)
The body of the instrument is a major determinant of the overall sound variety for acoustic guitars. The guitar top, or soundboard, is a finely crafted and engineered element often made of tonewood like spruce, red cedar or mahogany. This thin (often 2 or 3 mm thick) piece of wood, strengthened by different types of internal bracing, is considered to be the most prominent factor in determining the sound quality of a guitar. The majority of the sound is caused by vibration of the guitar top as the energy of the vibrating strings is transferred to it. Different patterns of wood bracing have been used through the years by luthiers (Torres, Hauser, Ramirez, Fleta, and C.F. Martin being among the most influential designers of their times); to not only strengthen the top against collapsing under the tremendous stress exerted by the tensioned strings, but also to affect the resonation of the top. The back and sides are made out of a variety of tonewoods such as mahogany, Indian rosewood and highly regarded Brazilian rosewood (Dalbergia nigra). Each one is chosen for their aesthetic effect and structural strength, and can also play a significant role in determining the instrument's timbre. These are also strengthened with internal bracing, and decorated with inlays and purfling.
The body of an acoustic guitar is a resonating chamber which projects the vibrations of the body through a sound hole, allowing the acoustic guitar to be heard without amplification. The sound hole is normally a round hole in the top of the guitar (under the strings), though some may have different placement, shapes or multiple holes.
As an instrument's maximum volume is determined by how much air it can move; the Dreadnought body size is popular amongst acoustic performers.
However, whilst the '00' pattern is a post-modern evolution in the wake of affordable wire-drawing and truss-turning technologies, musicians wishing to explore the nature of performance in the taverna or salon environments which overlapped early recording technologies may wish to consider the role of the 3/4-size as well as the Ordinary, or '0', guitar—particularly where a duo or ensemble is called for and space is at a premium.
Body (electric guitar)
Most electric guitar bodies are made of wood with a plastic pick guard. Boards wide enough to use as a solid body are very expensive, so the wood is rarely one solid piece. Most bodies are made of two pieces of wood with 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 polyester or nitrocellulose lacquer finish.
Pickups
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Pickups are electronic devices attached to a guitar that detect (or "pick up") string vibrations and allow the sound of the string to be amplified. Pickups are usually placed right underneath the guitar strings. The most common type of pickups contain magnets that are tightly wrapped in copper wire. Pickups work on a similar principle to a electrical generator in that the vibration of the strings causes a small voltage to be created in the coils surrounding the magnets. This signal is later amplified by an amplifier.
Traditional electric pickups are either single-coil or double-coil. Double-coil pickups are also known as humbuckers for their noise-cancelling ability. The type and model of pickups used can greatly affect the tone of the guitar. Typically, humbuckers, which are two magnets attached to each other and each wrapped in copper wire, are used by guitarists seeking 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. However, a disadvantage of single coil pickups is mains-frequency (60 or 50 hertz) hum. Some guitars need a battery to power their pickups and/or pre-amp; these guitars are referred to as having "active electronics", as opposed to the typical "passive" circuits.
The Fender Stratocaster type guitars generally utilize 3 single coil pickups, while the Gibson Les Paul types use humbucker pickups.
A further type of pickup is the piezo pickup. These employ piezoelectricity to generate the musical signal and are popular in hybrid electro-acoustic guitars. Usually, a crystal is located in the saddle under each string. When the string vibrates, the shape of the crystal is distorted, and this change in shape produces a tiny voltage that can be amplified and manipulated.
Some guitars have what is called a hexaphonic pickup. These pickups are also piezo pickups. "Hex" is a prefix meaning six. In a hexaphonic pickup there is a separate piezo pickup wired for each of 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 modelling the vibration. This results in a guitar which is able to mimic many vintage models, as well as output alternate tunings (e.g. Drop D) without the need to adjust the strings. The benefits of using a piezo pickup include the ability to bend strings and use palm/neck muting. Another use for hexaphonic pickups is to send the signal (that is the six separate 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 sounds can closely mimic a piano, trumpet or other brass instrument, harmonica or any of numerous other instruments.
Electronics
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 specialised 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.
Lining, Binding, Purfling
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.
Bridge
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 guitars, the bridge holds the strings in place on the body. There are many varied bridge designs. There may be some mechanism for raising or lowering the bridge to adjust the distance between the strings and the fretboard (action), and/or fine-tuning the intonation of the instrument. Some are spring-loaded and feature a "whammy bar", a removable arm which allows the player to modulate the pitch moving the bridge up and down. The whammy bar is sometimes also referred to as a "tremolo bar" (see Tremolo for further discussion of this term - the effect of rapidly changing pitch produced by a whammy bar is more correctly called "vibrato"). Some bridges also allow for alternate tunings at the touch of a button.
On almost all modern electric guitars, the bridge is adjustable for each string so that intonation stays correct up and down the neck. If the open string is in tune but sharp or flat when frets are pressed, the bridge can be adjusted with a screwdriver or hex key to remedy the problem. In general, flat notes are corrected by moving the bridge forward and sharp notes by moving it backwards. On an instrument correctly adjusted for intonation, the actual length of each string from the nut to the bridge saddle will be slightly but measurably longer than the scale length of the instrument. This additional length is called compensation, which flattens all notes a bit to compensate for the sharping of all fretted notes caused by stretching the string during fretting.
Pickguard
Also known as a scratchplate. This is usually a piece of plastic or other laminated material that protects the finish of the top of the guitar. In some electric guitars, the pickups and most of the electronics are mounted on the pickguard. On acoustic guitars and many electric guitars, the pickguard is mounted directly to the guitar top, while on guitars with carved tops (for example, the Gibson Les Paul), the pickguard is elevated. The Pickguard is more often than not used in styles such as flamenco, which tends to use the guitar as a percussion instrument at times, rather than for instance, a classical guitar.
