Introduction to the classical guitar
The classical guitar, also known as a Spanish guitar, is a member of the guitar family used in classical music and other styles. As an acoustic wooden string instrument with strings made of gut or nylon, it is a precursor of the modern steel-string acoustic and electric guitars, both of which use metal strings.
Classical guitars derive from instruments such as the lute, the vihuela, and the gittern (the name being a derivative of the Greek “kithara”), which evolved into the Renaissance guitar and into the 17th and 18th-century Baroque guitar. The modern classical guitar was established by the late designs of the 19th-century Spanish luthier, Antonio Torres Jurado.
The materials and methods of classical guitar construction may vary, but the typical shape is either the modern classical guitar or a historic classical guitar similar to the early Romantic guitars of Spain, France, and Italy.
Classical guitar strings, once made of gut, are now made of materials such as nylon or fluoropolymers (especially PVDF), typically with silver-plated copper fine wire wound about the three lower-pitched strings (D, A, and low E in standard tuning).
Physical characteristics and parts of the classical guitar
The classical guitar is distinguished by a number of characteristics:
- Acoustic resonance: the sound of the plucked string is amplified by the soundboard and the resonant cavity of the guitar.
- Six strings: though some classical guitars have seven or more strings.
- Nylon strings: all six strings are nylon (or nylon wound with metal), unlike the metal strings on other acoustics. Nylon tension is much lower than steel; the lower three “bass strings” are commonly wound with silver-plated copper.
- Lighter structure: because of the low string tension, the neck can be made entirely of wood without a steel truss rod, and interior bracing can be lighter.
- Neck width: typical modern six-string classical guitars are 48-54 mm wide at the nut, compared to around 42 mm for many electric guitars.
- Fingerboard: normally flat and without inlaid fret markers (or dots only on the side). Steel-string fingerboards usually have a slight radius and inlays.
- Right-hand technique: classical guitarists use the right hand to pluck; players may shape fingernails for a brighter tone and feel.
- Strumming: less common in classical; often referred to by the Spanish term rasgueo, or for strumming patterns rasgueado, using the backs of the fingernails. Rasgueado is integral to flamenco guitar.
- Related design: the overall design of a classical guitar is similar to the slightly lighter and smaller flamenco guitar.
Parts
Parts of typical classical guitars include:
- Headstock
- Nut
- Machine heads (pegheads, tuning keys, tuners)
- Frets
- Neck
- Heel
- Body
- Bridge
- Bottom deck
- Soundboard
- Body sides
- Sound hole (with rosette)
- Strings
- Saddle (bridge nut)
- Fretboard
Fretboard
The fretboard (also called the fingerboard) is a piece of wood embedded with metal frets that constitutes the top of the neck. It is flat or slightly curved. The curvature is measured by the fretboard radius: the radius of a hypothetical circle of which the fretboard's surface is a segment. A smaller radius means a more noticeably curved board. Fretboards are most commonly made of ebony, but may also be made of rosewood, other hardwoods, or phenolic composite (“micarta”).
Frets
Frets are metal strips (usually nickel alloy or stainless steel) embedded along the fingerboard at points that divide the string length mathematically. Pressing a string just behind a fret shortens its vibrating length to produce a higher pitch. Adjacent frets are spaced so each step is one semitone—the twelfth root of 2 (≈ 1.059463). The 12th fret halves the string length (one octave), and the 24th fret (if present) halves it again. Every twelve frets represents one octave, yielding the 12-tone scale in equal temperament.
Neck
A classical guitar's neck comprises the frets, fretboard, tuners, and headstock on a long wooden extension. The fretboard wood usually differs from the rest of the neck. Bending stress on the neck can be considerable, particularly with heavier gauges. The most common scale length is 650 mm (measured nut to 12th fret, doubled), though scale lengths from 635-664 mm or more are used.
Neck joint or “heel”
This is where the neck meets the body. In the traditional Spanish neck joint, the neck and block are one piece, with the sides inserted into slots cut in the block. Other necks are built separately and joined with a dovetail, mortise, or flush joint. These joints are usually glued and may be reinforced with mechanical fasteners. Many manufacturers now use bolt-on fasteners. Some believe Spanish one-piece neck/heel blocks and glued dovetails have better sustain, but tests have not confirmed this.
Body
The body is a major determinant of the overall sound. The guitar top, or soundboard, is a finely crafted element often made of spruce or red cedar, about 2-3 mm thick, and strengthened by internal bracing. The back is often rosewood (Brazilian rosewood is especially coveted), though mahogany and other woods are also used.
Binding, purfling, and kerfing
The top, back, and sides are very thin, so a flexible piece of wood called kerfing (kerfed so it can bend) is glued where the rim meets the top and back. This interior reinforcement provides 5-20 mm of solid gluing area for these corner joints.
Bridge
The bridge transfers vibration from the strings to the soundboard, which vibrates the air inside the guitar, amplifying the sound. The bridge holds the strings on the body. The position of the saddle-a strip of bone or plastic that supports the strings—sets the distance to the nut and thus affects intonation.
Guitar tuning and the standard tuning
A variety of different tunings are used. The most common by far, which one could call the "standard tuning" is:
- E' - B - G - D - A - E
The order above runs from the 1st string (highest-pitched, spatially the bottom string in playing position) to the 6th string (lowest-pitched, spatially the upper string), which is comfortable to pluck with the thumb.
