A Gibson SJ200 model.
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String instrument | |
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Classification | String instrument (plucked) |
Hornbostel–Sachs classification | 321.322-6 (Composite chordophone sounded by a plectrum) |
Playing range | |
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The steel-string acoustic guitar is a modern form of guitar that descends from the classical guitar, but is strung with steel strings for a brighter, louder sound. It is often referred to simply as an acoustic guitar, though the nylon-strung classical guitar is also sometimes called an acoustic guitar.
The most common type is often called a flat top guitar, to distinguish it from the more specialized archtop guitar and other variations.
The standard tuning for an acoustic guitar is E-A-D-G-B-E (low to high), although many players, particularly fingerpickers, use alternate tunings (scordatura), such as "open G" (D-G-D-G-B-D), "open D" (D-A-D-F♯-A-D), or "drop D" (D-A-D-G-B-E).
There are many variations in construction and materials used in steel-string guitars. Different combinations of woods and construction elements (for example, how the top is braced) affect the timbre or "tone" of the guitar. Many players and luthiers are convinced that a well-made guitar's tone improves over time. This is believed to be due to the decrease in the content of hemicellulose, crystallization of cellulose, and changes to lignin over time, all resulting in the wood gaining better resonating properties.
Acoustic guitars are commonly constructed in several different body types. In general, the guitar's soundbox can be thought of as composed of two connected chambers: the upper bouts and lower bouts (a bout being the rounded corner of an instrument body), which meet at the waist, or the narrowest part of the body face near the soundhole. The proportion and overall size of these two parts helps determine the overall tonal balance and "native sound" of a particular body style – the larger the body, the louder the volume.
Any of these body type can optionally incorporate a "cutaway." A cutaway guitar has a redesigned upper bout that removes a section of the soundbox on the underside of the neck, hence the name "cutaway." This allows for easier access to the frets that are located on top of the soundbox past the heel of the neck. The tradeoff is reduced soundbox volume, and often a change in bracing, which can change the resonant qualities and hence the tone of the instrument.