An acoustic guitar is a musical instrument in the string family. When a string is plucked its vibration is transmitted from the bridge, resonating throughout the top of the guitar. It is also transmitted to the side and back of the instrument, resonating through the air in the body, and producing sound from the sound hole. The original, general term for this stringed instrument is guitar, and the retronym 'acoustic guitar' distinguishes it from an electric guitar, which relies on electronic amplification. Typically, a guitar's body is a sound box, of which the top side serves as a sound board that enhances the vibration sounds of the strings. In standard tuning the guitar's six strings are tuned (low to high) E2 A2 D3 G3 B3 E4.
Electric guitars, first patented in 1937,use a pickup and amplifier that made the instrument loud enough to be heard, but also enabled manufacturing guitars with a solid block of wood needing no resonant chamber. A wide array of electronic effects units became possible including reverb and distortion (or "overdrive"). Solid-body guitars began to dominate the guitar market during the 1960s and 1970s; they are less prone to unwanted acoustic feedback. As with acoustic guitars, there are a number of types of electric guitars, including hollowbody guitars, archtop guitars (used in jazz guitar, blues and rockabilly) and solid-body guitars, which are widely used in rock music. The loud, amplified sound and sonic power of the electric guitar played through a guitar amp has played a key role in the development of blues and rock music, both as an accompaniment instrument (playing riffs and chords) and performing guitar solos, and in many rock subgenres, notably heavy metal music and punk rock. The electric guitar has had a major influence on popular culture. The guitar is used in a wide variety of musical genres worldwide. It is recognized as a primary instrument in genres such as blues, bluegrass, country, flamenco, folk, jazz, jota, ska, mariachi, metal, punk, funk, reggae, rock, grunge, soul, disco, and pop.
Antonio de Torres designed an classical guitar in Spain in the 19th century. The timbre of the sound, its strength and length are determined by the properties of the wood from which the soundboard is made, its construction, as well as every element of the body and neck. The term modern classical guitar sometimes distinguishes the classical guitar from older forms of guitar, which are in their broadest sense also called classical, or more specifically, early guitars.
Jazz guitar may refer to either a type of electric guitar or a guitar playing style in jazz, using electric amplification to increase the volume of acoustic guitars. Jazz guitar playing styles include comping with jazz chord voicings (and in some cases walking bass lines) and blowing (improvising) over jazz chord progressions with jazz-style phrasing and ornaments. Comping refers to playing chords underneath a song's melody or another musician's solo improvisations.