The dreadnought is a type of acoustic guitar body developed by guitar manufacturer C.F. Martin & Company. The style, since copied by other guitar manufacturers, has become the most common for acoustic guitars.
At the time of its creation In 1916 the word dreadnought referred to a large, all big-gun, modern battleship of the type pioneered by HMS Dreadnought in 1906. A body much larger than most other guitars provided the dreadnought with a bolder, perhaps richer, and often louder tone. It is distinguished by its size and square shoulders and bottom. The neck is usually attached to the body at the fourteenth fret.
Martin dreadnought guitars are also known as "D-size" guitars, or, colloquially among musicians, as dreads. Their model numbers consist of "D-" followed by a number, such as "D-18" and "D-45". The higher the numerical designation, the more decorative ornamentation on the instrument.
The dreadnought style was originally developed in 1916 and was manufactured by Martin specifically for retailer the Oliver Ditson Company. The model was retired after dismal sales. In 1931, after revising the design, Martin began producing dreadnought guitars under its own brand, the first two models being the D-1 and D-2, with bodies made of mahogany and rosewood respectively.
The popularity of and demand for Martin dreadnought guitars was increased by their use, almost exclusively, by folk musicians of the mid-20th century, including most bluegrass guitarists. Today they are considered the standard guitar of bluegrass music, used by many bluegrass musicians to produce a signature sound of that genre.
Martin dreadnoughts manufactured prior to 1946 are highly desired by musicians due to their loud volume and exceptional tone due to the use of scalloped bracing.[jargon] It is not uncommon for these guitars to sell for in excess of $30,000.
The Gibson Guitar Company's initial response to the Martin dreadnought was the round-shouldered J-35, which it introduced in 1934. It introduced its first square shouldered guitar, the Hummingbird, in 1960.