Guitar/Anatomy of a Guitar

This is an overview of the design, construction and components of the acoustic and electric guitar.

Overview of Components

1 Headstock

2 Nut

3 Tuning pegs

4 Frets

5 Truss rod

6 Inlays

7 Neck

8 Neck joint

9 Body

10 Pickups

11 Pots (volume and tone)

12 Bridge

13 Pick-guard or Scratch-plate

14 Back

15 Sound board (top)

16 Sides of the body (ribs)

17 Sound hole

18 Strings

19 Saddle

20 Fretboard (or fingerboard)

On Acoustics and Electrics

Body

The body of a guitar consists of a treble or upper bout and a bass or lower bout. The waist is the narrow section that divides them.

The body is one of the most important factors in determining the overall tone of a guitar. It provides the resonance that shapes the tonal qualities. It determines the volume of acoustics and affects the sustain of electrics. The resonance is affected by the type of wood used, whether the body is made from layered (ply) woods or a single piece, whether it is hollow or solid and the shape and size

The woods listed below are used in the construction of both the acoustic and the electric guitar.

Tone wood

• Agathis (also known as Commercial Grade Mahogany or Poor Man's Mahogany) is a type of pine that grows in East Asia. It is a plantation-wood used mainly for building cabinets. It is cheap and usually used in the construction of budget guitars. Its tone is similar to mahogany but more bland sounding with a less complex response.

• Alder is a light-weight wood that provides a clean balanced tonal response and good resonance. Its soft tight porous structure is similar to basswood but with a bolder hard grain pattern that adds to the stiffness and makes it more robust. Alder has a medium light tan color and provides a balanced tone across the frequency range with a slight upper mid-range producing a clean sound. Its resonance provides a good dynamic range.

• Ash offers two varieties for guitar construction and they differ in tone. Ash has an open grain pattern which requires a lot of lacquer to seal and this may result in less sustain than other woods. Ash is typically used in mid-range priced guitars.

• Northern hard ash (also known as Baseball Bat Ash) is hard, heavy and dense. This gives it a bright tone and longer sustain.

• Swamp Ash (also known as Southern Soft Ash) comes from swamps in the Southern USA. Swamp Ash grows underwater which makes the wood light-weight and porous. Many Fender guitars from the 1950s were built with Swamp Ash. It has hard grain lines between its softer layers and a creamy light tan color with bold darker grain patterns. Its tonal qualities are a very nice balance of brightness, warmth and dynamic range with clear bell-like highs, slightly scooped mids and strong lows. Since it has good resonance across the whole frequency spectrum it can sound quite complex.

• Basswood is a light-weight (lighter than Alder) close-grained wood with a consistent and tight grain pattern. Its very soft with light colors that range from almost white to medium tan. Because it dents easily; it requires a hard finish (such as polyester) and good engineering to allow the screws and screw-holes to hold the parts. The installation of a tremolo system on such a softwood also means the body needs to be thicker to prevent cracking. Tonally, basswood has a warm soft tone which attenuates both the high and extreme low frequencies. It also creates a pronounced midrange fundamental frequency response and a reduced smoother high-end response. The tonal response compared with other softwoods such as ash and alder is less complex with a narrower dynamic range. Basswood doesn't excel in clean sounds though when coupled with distortion and overdriven amplifier produces a metal-lead sound much favoured by some rock guitarists. It is used in the construction of budget guitars and expensive guitars. Steve Vai's JEM is an example of a basswood guitar in the higher price range.

• Cedar became popular in the mid-twentieth century after master luthier Jose Ramirez III of Madrid pioneered the use of red cedar as a substitute for the increasingly scarce European spruce. It is now considered one of the world's premier tonewoods.

• Mahogany is a highly dense, heavy wood with a fine, open grain and large pores. The color is reddish brown. Tonally, it provides good low frequencies, a compressed mid-range and smooth sounding highs. Overall, its tone is mellow, soft and warm with a full and thick quality. Its density provides excellent sustain and also makes it less susceptible to dents and scratches. Its density and weight have led some manufacturers to experiment with a thinner body as seen in the Ibanez S series.

• Nato is another type of eastern mahogany though most current stock now comes from South America. It is also a commercial grade wood used in cabinet building. It has a bright tone with pronounced midrange but lacks in sensitivity and punch compared with other varieties of mahogany. Nato is used by the manufacturer B.C. Rich for their Assassin range.

North-American Spruce

• Maple is used for the backs and sides of more expensive acoustics like the J200 series by Gibson. Though not generally used as a table for flat-topped instruments; it is the wood of choice for arched top guitars, mandolins, and the violin family of instruments. Its usually white in color with tight pores and thin grain lines. There are two main types of American maple:

• Eastern Hard Maple (also known as Hard Rock Maple or Sugar Maple and usually associated with maple syrup) is an excellent tonewood. As named, it is very hard and dense with a medium weight which makes it difficult to work and therefore it is usually reserved for necks. When used for the body, it provides a bright sound with very strong highs and upper mid-range but quieter bass frequencies. Overall, hard maple has a very long sustain. Eastern hard maple can exhibit a figure (grain pattern) called the "bird's eye" whose aesthetic appeal has led to it being used for guitar tops and backs usually bookmatched.

• Western Soft Maple (also known as Big Leaf Maple) is much lighter in weight than Hard Maple. It has a bright tone with good bite and attack though not as brittle as hard maple. Its tonal qualities produce singing highs with a tight low-end. This kind of maple is often seen with a figure called "flame" or "curl" and less commonly a figure called "quilt".

• Rosewood is used for the backs and sides of acoustics and also for fingerboards. It possesses an extremely high density making it very reflective acoustically. Its color is dark brown with reddish, purple or orange streaks running through it. There are many varieties of rosewood that are suitable for guitar construction.

• Poplar is a wood favoured by manufacturers who design budget guitars; especially by Danelectro as a center block with masonite used on the top and bottom. Due to the resurgence in popularity of the garage bands of the 1950s; guitars that use poplar are relatively expensive for such a budget wood. It is a closed grain wood with a greyish-green color and similar to alder in weight and tone.

• European Spruce is a premium tonewood used in the design of many stringed instruments including the violin, viola and lute. Increasing scarcity has resulted in the use of substitutes such as the North American species of spruce and red cedar.

• Walnut is a medium hard wood with a strong grain pattern. Its body has a constant density. It is harder, heavier and more dense than mahogany and therefore closer to maple. Tonally, it is warmer than maple with a solid low-end. The mid-range is relatively complex and the high-end is smooth and bright. Due to its density, it provides good sustain.

Body top

Some electric guitars have an extra top added to the body to blend the tonal qualities of different types of wood together. Maple with figuring is a popular top and produces a pronounced look and tone (adds brightness). Body tops are not used on acoustics since the layering of two pieces of wood for the table would inhibit the resonance and dull the tone.

Bridge

Bridge

The bridge is found on the lower bout of the body and its function is to allow the strings to sit at a relative height to the fretboard. Depending on the guitar, the strings may terminate at the bridge or just pass over it. On electric guitars the bridge can be raised or lowered; using two screws (thumbscrews which can be rotated with the fingers or traditional screws requiring a screwdriver) at either end of the bridge. This is discussed further in the Adjusting the Guitar section.

The bridge of an acoustic consists of two parts; a saddle and the tie block. Saddles are either a piece of plastic or polished bone and like the electric guitar bridge keep the strings at a relative height to the fretboard. Saddles are made with a smooth top edge (no notches) and the base of the saddle is seated in a groove cut into the tie block. The wood tie block of a classical guitar is glued to the lower bout and acts as a string terminator. A classical guitar string is pushed through the hole in the tie block and the string is then brought back under itself three or four times and pulled tight to form a knot. Once the saddle is seated in the groove of a tie block the tension of the strings clamp it. For steel string acoustics the same parts are used; saddle and tie block but due to the strings having terminating end balls there is no need to knot. Unlike the bridge of electrics, the saddle and tie block on acoustics are not made to be adjustable; they are set to the correct height by the manufacturer. Adjustments to the height of the saddle are possible though this is usually best left to a luthier since any shaving (lowering) of the saddle will be permanent.

The design of bridges varies greatly between different manufacturers and the above generic descriptions may not apply to some guitars. Regardless of the design the main purpose of all bridges is to maintain the strings at a relative height to the fretboard.

Fretboard and Frets

The fretboard (or fingerboard) is a piece of wood that is glued to the front of the neck. These are commonly made of rosewood though other hard woods, such as ebony for classical guitar fretboards, may also be used. Embedded in the fretboard are a number of metal frets (fret-wire) usually numbering 20 to 24. Strings are pressed down behind a fret which changes the length of string that is free to vibrate therefore producing a different note. A simple demonstration is to be found on the 12th fret. On all guitars this is the fret that divides the string exactly in half and produces a note an octave higher than the open note. Any open string that maintains its original tension and is halved produces its octave; the same principle applies to all stringed instruments including the piano and violin.

There are a variety of fret designs. Jumbo frets are higher and wider than normal frets and require less fretboard contact to sound a clear note. Medium frets are closer to the board and must be firmly in contact with the fretboard to sound a clear note. Some guitarist prefer jumbo frets due to the ease with which you can bend strings and the faster play offered by less fretboard contact. As with many design elements of the guitar this is a subjective area that is more personal preference rather than advantage. Good technique is not dependent on fret size

The first fret is the one nearest the nut. Some manufacturers (notably Gibson) place a "zero" fret immediately after the nut which maintains good intonation and action on flatter fretboards and wider necks. The strings sit on the zero fret therefore bringing the sound of the open string nearer to the quality of a fretted note.

Most fretboards have decorative inlays on the 3rd, 5th, 7th, 9th and 12th frets which serve as markers for the guitar positions. Fetboard inlays can be highly decorative or simple shapes. On more expensive guitars they are usually made of mother of pearl or abalone.

Headstock (Head)

Headstock

The headstock lies at the end of the guitar's neck. The purpose of the headstock is to support the tuners, which terminates the strings of the instrument. The tuners are attached to tuning pegs and this allows the guitarist to lower or raise the pitch of the string. A secondary purpose of the headstock is identification; many guitar manufacturers use a distinctive headstock shape, often in combination with a logo and model information.

Neck

The neck can be a single piece of wood or several pieces glued together and cut to shape. The fretboard is a seperate piece of wood that is attached to the neck. Necks can be glued to the body (set neck) or bolted on. Set necks are usually found on acoustic guitars and many other instruments; including the violin, lute and cello. The bolt-on neck is a design feature of electric guitars. Most necks are wood though alternative materials, such as carbon fibre composites, have been used.

Nut

All strings pass through a nut at the headstock end of the fretboard. Its function is to maintain correct string spacing and alignment so that the strings feed into their respective tuning pegs. On acoustic guitars the nut and saddle are usually made of the same material. Electric guitars commonly use plastic or synthetic nuts though sometimes metal is used. As tremolo bars can cause tuning problems, guitars equipped with them usually have some manner of locking nut, where the strings are clamped down.

Tip: Luthiers tend to lubricate the nut grooves so that the strings move smoothly without friction. You can do this at home with a soft graphite pencil; the graphite deposited in the grooves acts as a lubricant. There's no need for excessive marking with the pencil just a few swipes through the groove should deposit enough graphite.

Pick Guard

Tuning Pegs

This is a flat piece of plastic attached to the body below the sound hole or surrounding the pickups. It prevents the body from being scratched by the pick. Some electric guitars have raised pick guards; so that when you strum through a chord your pick is directed out and away from the pots and strings. Pick guards sometimes need replacing due to wear or damage and in the case of expensive or rare guitars (which may have a tortoise shell pick guard) should be replaced by an experienced luthier. The pick guard is sometimes called a scratch plate.

Sound Hole

Sound holes are found on all acoustics. Their primary purpose is to allow the air pressure to stay equalized so that the soundboard can vibrate. Most sound holes are round, but some guitars (archtop guitars) have violin style, f-shaped sound holes. Round sound holes usually have a decorated edge based on a geometrical design. On modern guitars these decorations are machine-made though some luthiers of expensive guitars use the traditional method of laying by hand small pieces of exotic woods.

Truss Rod

Steel-string acoustics and electric guitars have a steel truss rod that runs through the neck under the fretboard. Strengthening the neck with a truss rod counteracts the tension exerted by the strings and allows the curvature of the neck to be adjusted. Classical guitars do not require a truss rod due to the low tensile strength and high elasticity of nylon strings. Some less expensive steel-string acoustics do not have a truss rod. Adjusting the truss rod can have a marked effect on the action, tuning and playability of a guitar and should be left to a luthier. Excessive adjustments to the truss rod can render a guitar unplayable and should be avoided.

Tuning Pegs

Tuning pegs are used to raise and lower the pitch of the strings. Acoustics usually have two rows of three pegs; which when the guitar is held as normal presents one row at the top of the headstock and one row at the bottom. Electric guitars may have tuning pegs in a single row running along the top of the headstock (Fender Stratocaster) or use the the acoustic guitar layout (Gibson Les Paul).

The tuning pegs act as string terminators and it is essential for tuning stability that they suffer no defects. Tuning pegs that are misaligned, have play or excessive resistance to turning may need replacing or repair. Tuning pegs can be mounted to a plate (three on a single plate for acoustics) or be attached to the headstock as individual pegs (Fender Stratocaster); both designs rely on small screws to fix the pegs (or plate) to the headstock. Due to the tension of the strings and the constant turning of the pegs these screws may loosen; it is recommended that you check that they are screwed in tightly though never over-tighten which may in itself cause alignment problems or damage to the screw head.

Electric Guitar

Pickups

Three magnetic pickups on an electric guitar. From left to right they are a humbucker and two single coils.

A pickup is a magnet wrapped in a coil of copper wire. When a string is plucked, the vibration of the string causes magnetic flux, which is then amplified and played through a speaker. There are three types of pickups: passive single coils, passive humbuckers and active humbuckers.

Passive single coils are the standard pickup for Fender Stratocasters and their copies. They have a bright and twangy clean sound but traditionally have less output which results in a thinner sound. Due to their design they pick up the background hum caused by the induction of the AC current. Single coils are used by guitarists like Stevie Ray Vaughan. Some single coils, such as P-90, are larger than regular single coils, and thus warmer than a standard single coil. However they still retain more of a single coil sound and still can pick-up background hum. Another single coil design is the “Lipstick” (commonly found on Danelectro Guitars), where the entire pickup is placed in a metal enclosure with a small gap left between the two metal halves. It tends to be brighter sounding, and the magnetic field caused by the gap in the metal case causes some hum reduction.

Humbuckers use two magnetic coils operating in opposite magnetic polarity to cancel out the hum associated with single coils. They provide a warm, fat sound that is popular with metal and blues guitarists. Humbuckers are responsive to overdriven gain which creates a heavy saturated distortion. Some humbuckers allow coil tap (using only one of the coils) or parallel connection, which provides a sound similar to a single coil. Passive humbuckers offer a rich, thick distortion with natural decay; a sound favoured by the guitarist Dimebag Darrell from Pantera. Active humbuckers use battery or phantom power for enhanced sensitivity and longer sustain. The characteristic metallic distortion of active humbuckers can be heard in the work of the guitarist James Hetfield.

Although the different types of pickups have become associated with certain genres; guitarists often follow their own tastes. When chossing a guitar the overall sound (including the amp) should be the main consideration and it must be borne in mind that all pickups are perfectly capable of producing a tonal palette suitable for any genre the guitarist may wish to play.

Pickup Arrangements

There are many different arrangements for pickups. The most basic is a single pickup near the bridge.

• S + S - the original telecaster design uses two single coils. Telecasters have a percussive twang with lots of treble; a sound favoured by the guitarist James Burton. Even when using thick single coils (as found on the Jazzmaster and P90 Les Pauls), the tone is more emphasized on the treble side.

• S + S + S - three single coils are standard on Fender Stratocasters and Stratocaster copies.

• H + S + S - used on Stratocasters which are often called fat strats to distinguish them from the standard three single coil Stratocaster. The pick-up at the bridge is replaced by a humbucker. A favourite with guitarists who want the clean tone of single coils and the hum-free fat tone of a humbucker.

• H + H - the standard configuration for the Gibson Les Paul. Also known as the double fat strat configuration when mounted on a Stratocaster body.

• H + S + H - found on Ibanez's Steve Vai signature model and a favourite pickup arrangement for metal guitarists. Stratocasters using this configuration are called super strats.

• H + H + H - the standard pickup arrangement for the Gibson Firebird VII, SG Special and Les Paul Special.

Pickup Selector

On every electric guitar (except those with a single pickup) there will be a pickup selector. Guitars with two pickups have a three-way switch; allowing the guitarist to select either the pickup near the neck or the bridge. When the switch is in the middle position, both pickups are used.

On guitars with three pickups there is usually a five way switch. The positions are:

• neck pickup
• neck-middle
• middle pickup
• middle-bridge
• bridge pickup

Tremolo Bar

A tremolo bar stretches and slacks the strings. Pushing down on the bar lowers the pitch of the strings and pulling up raises the pitch. Rapidly pushing and releasing will produce a modulation in pitch called vibrato. Vibrato is often confused with tremolo (a volume modulation effect found on amps) hence the misnomer tremolo bar. Originally used just for vibrato; the modern improvements in guitar design, amps and effects has allowed guitarists to create a new palette of tremolo bar sound effects like the popular dive bomb.

The Fender Stratocaster shown here has multiple pickups, a whammy bar and volume and tone controls.

There are basically four kinds of tremolo:

• Bigsby tremolo - fitted at the bottom end of the body and with a limited pitch bend on both up and down. These distinctive looking tremolos are normally found on archtop guitars. Because of its limited range, it holds its tuning and is more stable than other non-locking tremolos that allow wider pitch bends.

• Vintage synchronized tremolo - (sometimes called the strat-type tremolo) can only down bend. This type of tremolo is more stable than the floating bridge tremolo though still prone to tuning problems.

• Floating bridge tremolo - this design allows wide bends of a tone or more in either direction though this greatly affects tuning stability. Poorly designed floating bridges on cheap guitars should be avoided since the flexibility of the design demands the highest quality in construction and components to ensure tuning stability.

• Locking tremolo (Floyd Rose) - this design locks the strings therefore ensuring that the original tension of the strings are not affected by the tremolo bar and the strings return to their original tension after use. The locking tremolo makes changing strings and tuning slightly more complicated though once in tune the locking tremolo maintains tuning stability far better than non-locking designs. You should always check your tuning every time you play since tuning is affected by other factors (moving from a cold room to a hot room can pull a guitar out of tune); the locking tremolo does not negate these factors.

Pots

Almost all electric guitars have at least two pots (potentiometer); one for the master volume and one for the master tone. Some guitars have four pots; two for volume and two for tone with one volume and one tone pot assigned to individual pickups. Fender Stratocasters typically have one master volume and one tone control for the neck and mid-pickup.

Electric Guitar Necks

3-screw bolt-on neck

This section describes the different methods used to attach a neck to an electric:

Bolt-on neck - the neck is attached to the body with bolts which are held by a mounting plate for increased stability. The mounting plate can make accessing the higher frets difficult so some manufacturers (notably Ibanez) use a hidden plate. The bolt-on neck is a standard design used by Fender.

Set neck - the neck is attached to the body with adhesive. This is the method used on acoustics and rarely is it used for mass-produced electrics. Electric guitars that feature a set neck have to be built to a high standard since once glued on the neck is permanent and can't be adjusted. Set necks are commonly found on more costly electric guitars. Gibson and Epiphone use set necks which is claimed to have these advantages over a bolt-on neck:

• warmer tone
• more sustain
• better access to higher frets

Thru-body neck - with this design the neck extends the entire length of the body. The strings, fretboard, pickups and bridge are all mounted on the thru-body neck. The ears or wings (side parts of the body) are glued or laminated to the central "stick". The wings may be bookmatched in order to give a symmetrical appearance. The thru-body construction method was pioneered by Les Paul as seen on The Log; one of his earliest electric guitar designs.

The thru-body neck is usually found on high-end guitars since the design is not favoured by mass-production manufacturers. It is more common on basses than guitars. The thru-body neck allows easier access to the higher frets because there is no heel and is considered by some guitarists to offer greater sustain.