Classical Guitar Parts – How The Classical Guitar Is Constructed
The acoustic guitar’s construction and materials have a major influence on the sound, and the various woods used in guitar manufacture are carefully chosen for their functional properties.
There are conservation issues associated with the use of wood, and research has tried to identify cheaper, more acoustically consistent synthetic alternatives, although with limited success so far.
The component parts of a classical guitar are shown below:
Photo: http://en.wikipedia.org/wiki/File:Acoustic_guitar_parts.png
The parts are as follows:
1. Headstock – wood, secures the strings at the top of the neck.
2. Nut – usually plastic or bone, and has slots to holds the strings in place. Neck width is usually 48-54 mm at the nut.
3. Machine heads (aka tuning keys, tuners) – geared mechanisms used to adjust the string tension. Rollers and pegs are usually plastic or bone, and the mechanism is metal.
4. Frets (fretwires) – 19 thin, slightly raised metal strips (usually nickel alloy or stainless steel) placed in grooves along the fretboard at semitone intervals. They become progressively closer, since a semitone rise in pitch is produced by shortening the length of the string by a factor of 1.0594. The string is pressed just behind the fret.
7. Neck – made from stable wood (usually cedar, although mahogany has been used). A steel truss rod isn’t required for classical guitars, which have a relatively low string tension.
8. Heel (neck joint) – the body and neck are joined at the heel at the 12th fret, which is half of the effective length of the string.
9. Body – forms a resonant cavity that strongly influences the sound. It has a flat bottom, curved sides and a soundboard that includes a sound hole. Bracing is used inside the body to strengthen the soundboard against the string tension, and to enhance the timbre.
12. Bridge – secures the strings at the lower end of the body. Its main purpose is to amplify the sound of the strings by transferring their vibrations to the soundboard. It is usually made from rosewood, and has purfling of wood, ivory or synthetic material, which is both decorative and protective.
14. Bottom (back) – forms the base of the guitar and consists of a thin, flat piece of wood (often rosewood) that is supported by bracing.
15. Soundboard (top, table, face) – the major influence on the guitar’s sound. It consists of a thin piece of softwood that is supported by bracing. The vibrational energy of the strings is transferred here by the bridge, and the soundboard in turn vibrates, moving the air inside the body, and amplifying the sound.
It is usually made from spruce, mahogany or red cedar. The important qualities of such woods include a close grain count and high stiffness to mass ratio (allows maximum output for the minimum input), resilience, light weight and resonance. It is usually 2 – 3 mm thick.
16. Body sides (ribs) – made from thin, curved pieces of wood. The bottom and ribs are traditionally made from Brazilian rosewood, but shortages in the last century meant that maple, Indian rosewood and others were frequently used instead. These close-grained hardwoods are tolerant of bending, and stable afterwards.
17. Sound hole with inlay – aids in the efficient projection of sound, and allows the face to vibrate freely. Most are decorated with a mosaic rosette.
18. Strings – six nylon strings, the bottom three of which are strands wound with fine metal (usually silver-plated copper). The usual tuning is E2 A2 D3 G3 B3 E4. The tension of each is about 60N.
19. Bridge saddle (bridge nut) – features grooves which hold the strings in place, and is usually made from plastic or bone.
20. Fretboard (fingerboard) – a flat thin wood (usually ebony) strip attached to the front of the neck, and embedded with metal frets. It is about 60mm wide at the body.
Not visible/labelled in the photo:
Binding, purfling and kerfing – Kerfing provides reinforcement at the rim. Binding is used to seal the endgrain on the back and sound board, and purfing is a decorative material that is placed next to the binding. These are usually made from wood or high grade plastic.
Bracing – thin strips of spruce (sometimes strengthened by carbon fibre) used on the inside of the soundboard and back. It is arranged in various patterns, (most commonly ‘fan-bracing’, developed by Torres in the 19th century), and provides structural support to the thin wood. Bracing has a major acoustic influence due to its effect on the elasticity of the wood.
Typical dimensions of the classical guitar are:
- Length: 960 – 1010mm
- String length: 650 – 660 mm
- Width (lower bout): 370mm; (waist): 240mm; (upper bout): 280mm
- Body length: 485mm
- Nut to body: 300mm
- Depth: 95 – 100mm
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