Wednesday 4 August 2010

Getting started: Anatomy of a Guitar

This is a general overview of the construction, components and design of the acoustic and electric guitar. Acoustic and electric guitars have many parts in common but electric guitars are slightly more complicated due to the need for pickups and controls.


 On Acoustics and Electrics

Body
The body is the most important characteristic of any guitar. It provides the resonance that shapes the tone of a guitar. It provides the volume (or heft) of an acoustic guitar and the sustain of an electric. On guitars the top smaller curved part closest to the strings is called the treble or upper bout and the bigger curved part is the bass or lower bout. The waist is the narrow section that divides them.

There are many factors that affect the body's tone: the type of wood used, the construction method (like layered or one-piece or hollow or solid-body) and the shape and size. There is a debate about whether the type of wood used for the electric guitar body actually makes a great difference to the tone. Some believe that a denser heavier wood gives a deeper sustain or richer tone but since it is mostly high-end manufacturers that use these kinds of wood, it may also be because the instrument is made using better construction methods. Others point out that the solid-body doesn't behave in the same way as the table of an acoustic which vibrates in sympathy with the strings and therefore the tonal differences produced by different woods is minor. 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. It is usually in a medium light tan. Alder provides a balanced tone across the frequency range with a slight upper mid-range producing a clean sound and 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.
          o Northern hard ash (also known as Baseball Bat Ash) is hard, heavy and dense. This gives it a bright tone and longer sustain.

          o 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. It is 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 so as 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 to other softwoods such as ash and alder) is not as complex and has a limited dynamic range . It is not a wood that excels in clean sounds but when played with distortion or overdriven amplifier provides a familiar metal-lead sound. 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. It has a punchy dynamic and its heaviness provide excellent sustain. Its density also makes it very stable and less susceptible to dents and scratches. Due to its heaviness it may not be comfortable to hold unless the body is similar to those of the Ibanez S series, which has a mahogany bodies that is thinner than most other designs.
  • Nato is another type of eastern mahogany though most current stock now comes from South America. It is also a commercial grade mahogany originally designed for cabinet building. Typically used as a mahogany substitute for budget guitars. It has a bright tone with pronounced midrange but lacks in sensitivity and punch compared to other varieties of mahogany. B.C. Rich used Nato for their Assassin range.
  • Maple is used for the back and sides. It is not common on flat-topped instruments, but it is the wood of choice for arched top guitars, mandolins, and violin-family instruments. It is usually white in color with tight pores and thin grain lines. These are the two most common kinds of American maple:
          o Eastern Hard Maple (also known as Hard Rock Maple or Sugar Maple) is usually used for maple     syrup but can also be used as an excellent tonewood. As named, it is very hard and dense with a medium weight. Its hardness makes it difficult to work with and therefore it is usually reserved for necks. As a body wood, 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. This is the kind of maple that can exhibit a figure called "bird's eye".
          o 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 (though very beautifully), a figure called "quilt".
  • Rosewood, though reserved for the back and sides of acoustic instruments is also sometimes used 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 rosewoods that are used for guitars.
  • Poplar was in the past only used for budget guitars; especially by Danelectro as a center block with masonite used on the top and bottom. However due to the resurgence in popularity of the old garage sounds of the 1950s, the 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.
  • Spruce For centuries European spruce has been the premium tonewood used for stringed instruments. Increasing scarcity has resulted in the increased 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 midrange is relatively complex and the top end is smooth and bright. Due to its density, it provides good sustain.

Body top
For high-end guitars, luthiers tend to incorporate an additional top to the body to blend the benefits of different types of wood together. Typically, the type of wood used is maple with figuring. While the figuring does not affect the tone, it does provides a much more pronounced look.
 
Bridge
The bridge is found between the middle and bottom of the body. Its function is to allow the strings to pass over it and sit at a relative height. Depending on the guitar, the strings may start at the bridge or they may only be supported by it. Most Electric guitars allow the bridge to be raised or lowered, allowing the action of the guitar to be finely adjusted. This is typically done by adjusting screws, either thumbscrews which can be rotated with the fingers or traditional screws requiring a screwdriver. This is discussed further in the Adjusting the Guitar section.

Acoustic guitar bridges usually have a saddle. A saddle is a piece of plastic or polished bone that is used for the string to rest on. The smoothness prevents the guitar from buzzing and it can also be used for very fine tuning. Synthetic bone substitutes are becoming more common.

Fretboard
On the front side of the neck is the fretboard or fingerboard. These are commonly made of rosewood but many other hard woods are also used. Embedded in the fretboard are a number of metal frets; usually 20 to 24. Strings are pressed down behind a fret to change the note that the open string will produce. There are a variety of fret designs; jumbo frets means tall frets and therefore you do not need to press down to the board, while medium means closer to the board and thus need to be pressed onto the board in order to be heard. The first fret is the one nearest the nut (see below), unless there is one immediately after the nut, which is called a "zero fret". Most fretboards have inlays on the 3rd, 5th, 7th, 9th and 12th frets which are decorative and also function as markers for quick recognition of guitar positions. Some also have inlays on the 1st, 15th and 17th.

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 of a guitar extends from the body. It can be a single piece of wood but often it is several pieces glued and cut to the proper shape. The fretboard is attached to the neck, along with the head stock at the end. Some necks are glued to the body (called a set neck) and others have it bolted on. Set necks are almost universal amongst acoustic guitars. The bolt-on or screw-on neck are most common in electric guitars. Most necks are wood though there are several alternative materials, such as carbon fibre composites. A few guitars are made entirely of one piece of wood, where the body is carved from one piece and sides are attached. These sorts of guitars often do not have truss rods.

See below for more details on electric guitar necks.

Nut
All strings pass through the nut at the end of the fretboard. It roughly divides the fretboard and headstock, and its function is to maintain proper string spacing and provide an endpoint for the string. On Acoustic guitars, the nut and saddle are usually made of similar material. Electric guitars commonly use plastic, synthetics, and sometimes metal nuts. As tremolo bars can cause tuning problems, guitars equipped with them usually have some manner of locking nut, where the strings are clamped down. Fender produces a roller nut, where the nut incorporates a system of ball bearings, making it similar to a locking nut, but without biting into the strings.

Pick Guard
This is a flat piece of plastic on the body of the guitar, beneath the sound hole or surrounding pickups. It prevents the body from being scratched by the pick. Some Electric guitars have raised pick guards, so when you strum through a chord, your pick is directed out and away from the volume and tone knobs (but also the strings). Most pick guards can be replaced by players, but it is best to take the guitar to an experienced luthier. The pick guard is also called a scratch plate.

Sound Hole
This is where the sound waves made by the strings exits the body. Most sound holes are round, but some Electric guitars (archtop guitars) have violin style, f-shaped sound holes.

Truss Rod
Most Acoustic and Electric guitars have a steel truss rod that runs through the neck under the fretboard. It counteracts the pull of the strings on the neck, strengthening it, and allows the curvature of the neck to be adjusted. Classical guitars do not require a truss rod, because there is less tension from their strings, and some less expensive acoustics do not have truss rods. Adjusting the truss rod is a step in setting up the guitar, but you should know what you're doing before you perform this adjustment.


Tuning Pegs
These are attached to the headstock, and these are where the strings end. They are used to raise and lower the pitch of the strings. There are two main styles, those found on steel string Acoustics and Electric guitars, where the tuning pegs are attached straight into the side of the headstock, and on classicals where they are perpendicular to the headstock. The style of tuning pegs on classicals resembles the tuning pegs on violins.
 
Electric Guitar

Pickups

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

Passive single coils have one electromagnet and are found on 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 style is the “Lipstick” style (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, however, use two magnetic coils, operating in opposite magnetic polarity, to cancel out the hum generated by single coils. They provide a warm, fat sound and it is interesting to note that they are used most in the metal and blues genres. Humbuckers allow you to use a lot of overdriven gain and you can make the guitar sound very heavy. Some humbuckers also allowed either coil tap (using only one of the coils) or parallel connection, which provide a sound similar to single coil. Passive humbuckers are for rich, thick, naturally decaying distortion, and they are used by artists like Dimebag Darrell from Pantera. Active humbuckers use battery or phantom power to provide enhanced sensitivity, and thus have longer sustain and can take heavy distortion. Active humbuckers are used most famously by James Hetfield of Metallica.

Ultimately, however, any pickup can be used for any genre: some people use humbuckers for blues and jazz, while others may use the single coil for the sound they prefer. It is also important to remember that amplifiers and effect pedals can greatly change the tone of any guitar.

There are many different arrangements for pickups. The most basic is a single pickup, typically near the bridge. There also the following:
  • S-S - telecaster style; due to the large spacing between, provide what is typically known as "country twang", a chirpy sound with lots of treble. Even when using thick single coils (eg Jazzmaster and P90 Les Pauls), the tone is more emphasized on the treble side.
  • S-S-S - Strat and and Strat copies
  • H-S-S - "Fat strat", basically the pick-up at the bridge is replaced by a humbucker. A common choice for people who may like both the clean tone and hum-free fat (and dirty) tone.
  • H-H - Gibson Les Paul, and common humbucker arrangement. Also known as "Double fat strat" when mounted on a Strat like body.
  • H-S-H - "super strat". Typically used for metal, such as Ibanez's Steve Vai signature model.
  • H-H-H - Gibson Firebird VII, SG Special, Les Paul Special.

Of course, these are some of the basic configurations, since a S-S-S configuration can be configure into H-S-H or even H-H-H through single-coil sized humbucker. A humbucker slot can easily utilize a much hotter super distortion type humbucker (essentially 2 single-coil sized humbucker connect together), giving output that is as high as an active pick-up.

On almost every electric guitar there will be a pickup selector that allows you to choose which pickups to use.

A 2 pickup guitar will usually have a 3 way switch, the first for the neck, the third for the bridge and the middle for both.

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

On guitars with 3 pickups there is usually a five way switch.
  •   neck
  •   neck-middle. In the case of H-S-H without coil tap, it will be two single coil in between
  •   middle
  •   middle-bridge. In the case of H-S-H without coil tap, it will be two single coil in between
  •   bridge pick-up.

For 2 humbuckers, there could be either 3 ways (as mentioned above for 2 pick-ups) or 5 ways:
  •  neck
  •  neck at parallel (which produce a tone similar to single coil)
  •  both humbuckers
  •  both humbuckers, each in single coil mode (inner coils)
  •  bridge humbuckers

Sometimes, instead of neck at parallel, it could be both humbuckers, each in single coil mode (outer coils); said to produce more of a telecaster-like tone.

While it is rare, some guitars, such as Fender Jaguar, Fender Mustang, and Red Special utilize independent switches for each pickup, which can provide even more flexibility.

Bridge
For electric guitars there are basically two kinds of bridge: those that have a tremolo (whammy) bar, and those that do not, (also known as hardtail). For the sake of discussion, we also include the tail end, where the string terminates.

A tremolo bar is a bar that stretches and slack the strings, causing the sound to change pitch. Pushing down on the bar lowers the pitch of the strings, and pulling up will raises the pitch. Rapidly pushing and releasing (or pushing and pulling for exaggerated effect) will produce a modulation in pitch, called vibrato. Vibrato is often confused with tremolo (modulation in volume), hence the misnomer tremolo bar. While traditionally used for vibrato, It is more commonly used for dive bombs and various other guitar tricks.

 
There are basically four kinds of tremolo:
  • Bigsby comes with a tail piece that natch at the bottom end of the body, it usually provide only a half pitch bend on both up and down. Typically installed on archtop guitars, though its modified version exists as Gibson Vibrola. Despite its limited range, it does go out of tune as easily and other non-locking tremolo.
  • Vintage synchronized tremolo, aka strat-type tremolo, can only down bend. Can go out of tune easily, though not as much as floating
  • Floating bridge tremolo Out of all non-locking tremolo, these can go out of tune most easily, due to the fact that it can upbend and downbend for two half-steps or more. On poorly designed version, these can go out of tune even during palm mute. However, it can be convert to downbend only, by tipping the "down" side of the bridge against the body.
  • Locking tremolos (Floyd Rose). These tremolos can stay in tune almost indefinitely. However, once set up it's hard to change tuning with these, and changing strings and setting up in the first place is a huge chore, and thus can be overly complicated for a beginner. The way to tell if it's a locking tremolo is to see if it has a set of locks at the nut section. The benefit of having a locking tremolo is that the guitar stays in tune, but you should always tune your guitar every time you play, even if you have locks (In the case of Floyd Rose, by microtuner).

The only way to rarely go out of tune is to either use the Floyd Rose tremolo or a hardtail (no tremolo). If you prefer to ease of setup while staying in tune with a tremolo, you can also try Yamaha's "finger clamp" locking tremolo, which requires no tools when setting up, or use locking tuners and roller nuts, as in Fender's locking tremolo.

As mentioned, a hardtail (no tremolo) bridge is great at staying in tune. However, it also has additional benefits, in that it also improved sound and sustain. The fixed bridge also makes it easier to perform string bends, and gives an altogether warmer and rounder sound than one with tremolo.

Despite such simple concept, there are at least three versions of ending the string:
  1. The first kind is the stop bar method, used from cheap budget types to expensive archtop and PRS guitars, where a stop bar that's mounted on top of the body holds the string's end. Sometimes it is also integrated to the bridge.
  2. The second kind is known as thru-body, where the string goes into the body; this enhanced sustain, but typically more expensive. the bridge, however, is a separate piece of hardware. Example would be Gibson's tune-o-matic. Despite this, strings still slide over the nut and saddles when playing/bending strings, just not as much as they do on a normal synchronized tremolo.
  3. The third kind of tail bridge is the fixed locking bridge, based upon the Floyd Rose tremolo except it is fixed; in this configuration, the string is clamped down, which ensure the string is stay in tune. Due to the fact that it's a fixed bridge, there are no spring cavity in the back; instead, the bridge is more or less mounted directly above the tail piece, which is usually thru-body. This is the best method to stay in tune. Currently, only Ibanez makes fixed locking bridge.

Switches and Knobs

Almost all electric guitars have a switch that changes which pickups are being used and at least two knobs, one for the master volume and one for the master tone. If the guitar has four knobs, then it has two volume and two tone, with each-volume-pair assigned to a pickup. Fender Stratocasters typically have one master volume and a tone control for the neck and mid pickup.

Do note that, unless it is an active pickup, the volume and and tone control are much closer to a set of filter for the signal. Even if you turn the amplifier to eleven, if the guitar's volume is set low, it won't generate enough current to drive the amplifier to overdrive. As for the tone, it acts as a low pass filter, which help "boost" a certain range of frequency.

Neck-joint
This is where the neck is connected to the body, and there are several different kinds of joins:
 
Bolt-on neck - as the name indicate, the neck is attached to the body by a series of bolts and mounting plate for stability. Typically, there should be no less than 4 bolts, otherwise it will start to be detestable (as demonstrated on CBS Fender guitars). The mounting plate, as well as a square-shaped joint, typically made accessing the upper frets difficult. To rectify it, some manufacturers, such as Ibanez, uses hidden plate bolt on, with the bolts mounted deeper into a smoothed body, while some like MusicMan have a contoured joint that follows the angled contour of joint (though still use metal plate); both results in an easy access for the upper frets. The standard Bolt-on is famously used by Fender, with Ibanez making all its bolt-on joins with hidden plates, even for the budget range.
 

Set-in neck - For acoustic guitars, this is the common joining but for electrics, this is typically reserved for more expensive guitars as it requires more careful manufacturing to ensure a good result. This method involves joining guitar neck and body with some sort of adhesive. This yields a stronger connection than a bolt-on neck, though not as strong as a neck-thru body joint. Gibson and Epiphone both use the set-in neck. It has the following advantage in comparison to bolt on:
  • Warmer tone
  • More sustain
  • Usually better access to top frets in comparsion to bolt-on necks utilizing a metal plate; even on a hidden-plate bolt on, due to the neck join can slope even more, set-in still give more access to the upper frets.

Thru-body necks involves extending the piece (or pieces, in a laminate construction) of wood used for the neck the entire length of the body. The strings, fretboard, pickups and bridge are all mounted on this piece. So-called ears or wings (i.e. 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 and they are often cut from one piece of wood. The thru-body construction method was pioneered by Les Paul, who made his "The Log" out of the same method.

As this is significantly harder to mass-produce than bolt-on or set neck constructions, it is primarily found on high-end guitars. It is somewhat more common in basses than in guitars. Neck-thru construction allows easier access to upper frets (those nearer the guitar body), because there is no need for a heel – the thickened area on the neck where it bolts to the body. Many musicians also hold the opinion that neck-through construction provides greater sustain, though guitar greats such as Eric Johnson, Eddie Van Halen, Steve Vai (Ibanez JEM) and Joe Satriani (Ibanez JS series) have managed quite well with hidden-plate bolt-on necks. Neck-through instruments supposedly stay in tune longer., and due to the fact that the string is on the entire piece of wood, it has much better sustain.

Set through can be seen as a modification of a thru-body neck, which is done by the following
  • A pocket in the instrument's body for insertion of neck, as in bolt-on method. However, the pocket is much deeper than usual one.
  • Long neck plank, comparable to the scale length, as in the neck-through method.
  • Glueing (setting) the long neck inside the deep pocket, as in the set-in method.

The result is usually told to have combined advantages of all these methods, mostly eliminating their disadvantages. Luthiers frequently cite:
  • improved tone and sustain (due to deep insertion and body made of single piece of wood, not laminated as in neck-through),
  • "warmer" tone (due to set joint)
  • comfortable access to top frets (due to lack of hard heel and bolt plate),
  • better wood stability.
The main disadvantage is a relatively complex construction method that leads to higher manufacturing and servicing costs. Another cited disadvantage is the inability or difficulty of adding a double-locking tremolo to the guitar, as the routing for cavities would interfere with deeply set neck.

Amplifier and effects
The amplifier is absolutely necessary when playing the electric guitar. Acoustic guitars with no internal pickup may be amplified with a microphone and a specifically built acoustic amp or PA. Different amplifiers will give the same guitar a different sound and some amps are more appropriate for certain genres of music. Many amplifiers have effects built in. The most common being distortion; often called overdrive. If the amplifier has a "lead" channel then this can be turned up to produce distortion. This is possible because the pre-amplifier (pre-amp) will overdrive the amplifier's tubes or transistors therefore causing the amplification not to be linear. The more the tubes and transistors are driven, the greater the distortion.

Turning up the pre-amplifier will increase the volume. To compensate amps also have a "gain" knob which can be turned down to reduce the volume after overdrive. Overdriving an amp can result in sounds loud enough to cause damage especially blown speakers. This can happen to small 25w amps as well as large rigs. If you have just bought an amp or have use of unfamiliar equipment then always turn down the gain when plugging in and slowly and carefully adjust to the appropriate level. Distortion can also be provided by effects pedals. Other on-board effects you may find on an amp are chorus, reverb, wah-wah, compression and delay.

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