Created | Updated Jan 6, 2012
A guitar is basically a box with strings stretched across it. As the string is plucked, it vibrates. This makes a very small amount of noise which is amplified by the sound reverberating about inside the box and then coming out of the 'sound-hole'.
The sound varies depending on the material, thickness, length and tightness of the string, and also the shape of the box as well as what it is made of. The top or 'soundboard' of the guitar is much more important than the back and the sides as this transfers the vibrations of the string to the box.
Of all different guitar types, the classical has the sweetest and fullest tone. Its biggest disadvantage is the lack of volume, which is one reason you don't find guitars in orchestras.
Types of Classical Guitar
There are two main types of 'Spanish guitar' today, the classical and the flamenco. It is not always easy to spot the difference but a flamenco guitar is usually lighter and has a lot of attack to the notes but little sustain. Visually the most obvious give-away is the 'golpeador' or tap plate which is often put on these guitars. This is done because the flamenco style involves percussive tapping on the top of the guitar. Also, flamenco guitars will have a lower action to aid playing speed.
How to Play a Guitar
The classical guitar is often considered the best to learn on. This is because the nylon strings are softer on the fingers than metal strings and classical guitars are usually cheaper. Also, although the high action and wide neck of the classical can make it more difficult to play than other types, such as the electric guitar, it does encourage you to learn the proper technique and not take short cuts which might be regretted later.
The strings on the classical guitar are plucked with the fingers on the right hand, if you are right handed. Tone variation comes from the amount of nail and skin that come into contact with the string as well the position on the string that it is plucked. Near the bridge, the tone is trebly and twangy, but near the neck, the tone is bassy and mellow. This is due to the distance from the bridge of the main vibration of the string. Sometimes picking or strumming is aided by a small flat device known as a plectrum or pick.
A different note is obtained on the guitar by holding a string down against the fingerboard between the 'frets'. Hold the strings down on the neck with the left hand while the fingers are placed just behind the frets. This shortens the length of the string vibrating so the frequency and therefore the pitch of the note is higher. The frets are positioned a semi-tone apart.
Classical Guitar Structure
A classical guitar is built as a shaped box. The sides are heated and then bent into shape and glued to the back and the top. To enable a good glue join, small pieces of wood lining are glued in the corners. The back and sides tend to be made of woods like Rosewood or Mahogany.
The top, which is the most important element of the guitar, is usually made of spruce or cedar wood. It is always a compromise. The top must be thin enough to vibrate nicely but strong enough to take the odd knock and change in temperature. To aid this, they have bracing struts on the inside which add rigidity and strength to the top. As mentioned earlier, the actual positioning of struts is very important to the sound as it helps determine what frequencies different parts of the top will vibrate at. It is not symmetrical - the bracing allows for the positioning of the strings.
Attached to this soundbox is the neck. This is nearly always made of mahogany and attached to the body with a glued dove-tail joint. There is a separate attached 'fingerboard' often made of rosewood or ebony to which metal frets are attached. The body joins the neck at the 12th fret (one octave above the open string). Unlike other guitars, the fingerboard on the classical is usually plain and unadorned.
The strings are attached to the body at one end and the head at the other. At the body end, there is a 'bridge' which is a piece of wood (usually rosewood or walnut) glued to the top. There are small holes at the back of this to tie the strings onto. The strings then pass over an insert in the bridge called the 'saddle'.
The saddle is traditionally made of bone or ivory but is usually made of plastic these days. Its height will affect the 'action' of the guitar (the height of the string above the fingerboard) and the tone. You need a fairly sharp angle as the string passes over the saddle to where it is anchored.
At the other end of the neck, the strings pass over an equivalent piece of material (only with slots cut in for the strings) called the 'topnut'. It is also important to get the angle and height right here for the same reasons.
The strings then pass through to the tuning pegs on the 'headstock'. Unlike a violin, which has tapered pegs (these must be pushed in to prevent slipping) the guitar has geared 'machineheads' which makes for much easier tuning.
When the strings are tuned to pitch, they are under a very great tension. As wood is flexible - this tension will bend the neck out of shape (like an archer's bow) if it is not strengthened in some way. To do this, most modern guitars have a metal 'truss rod' inserted in the neck. It is not adjustable on the classical guitar.
When strings are new, they will stretch. As this will make tuning unstable, guitar players will 'stretch in' their strings before playing. Nylon strings are the worst for this problem. The player must tune the string to pitch, stretch the string along its length and then retune. They do this until the string stops stretching.
The thicker, lower strings on the bass side have a nylon core with silver wound round the outside and are not as difficult as the thinner treble strings which are plain nylon1. The bass strings can be tied to the bridge with a simple knot, but the treble strings need to be wound round three or four times to prevent them slipping.
The History of the Guitar
The Guitar as an instrument has been around for hundreds of years, but different instrument names make it difficult to pin-point exactly when, but it is believed to have been invented by the Moors of North West Africa and its popularity spread through Europe in medieval times, becoming a particular favourite in Spain. Certainly by the late 1500s, there were some instruments about which were recognisable as guitars.
In those days, the shape was usually quite thin and the number of strings varied. There were several 'courses' where each 'course' would consist of two or three unison strings, like on a mandolin.
The soundhole rosette was often very ornate as was the rest of the guitar. A notable exception to this were those guitars made by Antonio Stradivari, the renowned violin maker. His instruments were excellent in sound, but elegant because of the plain simplicity of his designs.
Early instruments were often 'treble' four course guitars but by the mid 16th Century, the trend had moved towards a lower tuned five course instrument.
Tunings varied widely but by the middle of the 18th century, the A/D/G/B/E (the top five strings on a modern guitar) became standard. By the late 18th Century, the trend had moved to six courses with the bottom tuned to a low E and then there followed the move to six single strings.
Spanish guitars began using fan-bracing by 1803 at the latest. One Researcher has discovered this from personal experience, by examining an extremely rare Juan Pages guitar from Cadiz, made in 1803. Pages was considered one of the premier makers at the time, and he used a five fan bracing. Guitars from Germany, France, and elsewhere did not evolve as rapidly and they did use tranverse bracing until the mid 1800s, some even later than that.
Then in the late 1830s, a maker called Antonio de Torres made a larger but not heavier body adopting Pages' fan type strutting which made the guitar louder, with a greater tonal range, particularly in the bass.
Torres' designs were accepted world-wide and all classical guitars today are pretty much based on 'The Torres Pattern'.