Dreadnought (guitar type)

The dreadnought is a type of acoustic guitar developed by American guitar manufacturer C.F. Martin & Company. The style, since copied by other guitar manufacturers, has become one of the most common for acoustic guitars. In its most frequently encountered shape it is characterized by square shoulders, a relatively flat tail end, a wide waist with a large radius curve, and a 14-fret neck (i.e., 14 frets clear of the body) although when first introduced, the body was longer, with round shoulders, and only 12 frets clear of the body. 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.

Martin dreadnought guitars are known as "D-size" guitars, as opposed to their smaller equivalents (in increasing order of size, 0, 00, 000 and sometimes 0000 or M). 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. Size "D" represents (effectively) the largest in the Martin range; historically (pre-1900 or thereabouts), even smaller sizes were produced including 4, 3, 2 and 1, plus some intervening designations. Present Martin production also includes models "M" (sometimes known as 0000) and "J", which in overall dimensions are wider again than model "D", however are smaller in actual volume on account of a more narrow waisted design plus a shallower body depth.

From their introduction to 1933, all Martin dreadnoughts were in the "original" / long body, 12-fret neck, slotted head style, with a larger body volume (and different sound quality) than their successors. From 1934 onwards, the size and shape of most dreadnoughts changed to the "modern" (14-fret) style with a squarer, smaller body shape and 14 frets clear of the body, although a small number of "original" style dreadnoughts have remained in catalogue since that time and are preferred by certain players and collectors.