Dreadnought (guitar type)

A C.F. Martin & Company dreadnought

The dreadnought is a type of acoustic guitar body developed by American 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. 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.

History

Martin dreadnought acoustic guitar body shapes: 12-fret / larger body shape on left, 14-fret "square shoulder" (=modern) body shape on right

The dreadnought style was developed in 1916 by Martin specifically for the retailer 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 named the D-1 and D-2, with bodies made of mahogany and rosewood respectively; shortly after, these 2 styles were renamed the D-18 and D-28 with "D" indicating body size, and the numbers the timbers used and degree of ornamentation as per other Martin models of the time. Like their Ditson-branded precursors, these 2 models had large bodies, with neck joining the body at the 12th fret, and slotted headstocks holding the tuning mechanisms for the strings. In 1933, owing to a preference from players (especially those transitioning from the banjo) for more frets clear of the body, the body shape was changed to a slightly smaller, squarer shouldered design, which—in conjunction with a slightly adjusted bridge placement—permitted the neck to have 14 frets clear of the body (refer illustration). The "14 fret" design has become the standard for most succeeding instruments manufactured to the "D" body size, although the "12 fret" design has been retained in the Martin line for some special orders, certain 12-string models, and the "-S" designated D-18S, D-28S, D-35S and D-45S, with the "S" suffix, originally just denoting any non-standard custom feature, stabilizing as denoting the 12-fret variant from 1967 onwards. A small run of dreadnought guitars manufactured by Martin for the E.U. Wurlitzer store in Boston designated "SW" for "Special Wurlitzer" in the early 1960s also featured the 12-fret design.

The popularity of and demand for Martin dreadnought guitars was increased by their use by folk musicians of the mid-20th century, including most bluegrass guitarists. Dreadnoughts became the standard guitar of bluegrass music, used by many bluegrass musicians to produce a signature sound. While most players prefer the tone of the standard, 14-fret instrument, noted for its more penetrating sound especially when played with other instruments, a few prominent players—including Peter Yarrow of the group Peter, Paul and Mary, Norman Blake, and on occasion Paul Simon (per the cover of his 1974 Live Rhymin' release)—have still favoured the slightly different sonority produced by the 12-fret, larger body shape.

The Gibson Guitar Company's response to the Martin dreadnought was the round-shouldered Jumbo, which it introduced in 1934. It introduced its first square shouldered guitar, the Hummingbird, in 1960.

Since then, dreadnoughts have been made by nearly all major guitar manufacturers worldwide in both standard and single-cutaway forms.

Internal construction

Top bracing on Martin dreadnought guitars - scalloped (left) and non scalloped versions

Martin dreadnought guitars feature the classic, Martin-developed "X-braced" top which, together with additional tone bars and braces, permit the traditional "dreadnought" sound to be produced (refer illustration). Note, the two lowest tone bars are asymmetric to account for the different modes of vibration between the bass and treble sides of the instrument, so would be reversed for a left-handed model. Up until late 1944, the main X-braces were "scalloped" (selected areas reduced in mass) to achieve the best tonal response, but following that date the braces were first merely tapered, then left unscalloped to produce a more robust instrument that would withstand the use of heavy gauge strings without causing warranty work, which the company was keen to avoid; this makes the historic instruments manufactured between 1933 and 1944 of the highest value to both collectors and players. Scalloped bracing was reintroduced on selected new models (designated the HD-28 and HD-35) in 1976 in response to player demand; such instruments are advised to only be strung with light or medium gauge strings. The "H" portion of the "HD" designation refers to the use of herringbone trim, which roughly coincided with the use of the original scalloped bracing in the pre-1945 models, and was reintroduced in relevant new scalloped braced instruments as a cosmetic indicator of their construction type. Prior to mid 1939, the X-braces crossed at a position 1 inch from the soundhole (known as "high X" or "forward shifted" bracing), being moved back a little towards the lower bout after this date.

Other key developments of interest to both players and collectors was a switch from Brazilian to Indian rosewood (for the rosewood instruments, D-28 and upwards) in late 1969, and from a small maple bridgeplate to a larger rosewood one in 1968. Both of these changes have generally been seen as undesirable from a tonal viewpoint, leading to considerably more interest (and higher sale prices) for pre-1969 instruments than their later counterparts (Brazilian rosewood, now rare and expensive, has nevertheless been used since on some expensive models and special editions).

Almost all Martin dreadnoughts have been manufactured with a 2-piece back, with the exception of the D-35 (introduced 1965) plus its later variants such as the HD-35 which feature a 3-piece back. The D-35 also has slightly narrower top braces (1/4 inch rather than the 5/16 inch used for other models) which, together with the different bracing of the back, may contribute to its different tonal response in comparison with other rosewood models featuring the 2-piece back.

See also

• Chiterra sarda, a traditional large-bodied guitar from Sardinia

External links

• What is a dreadnought guitar? on Sixstringsacoustic website
• What is a dreadnought guitar? on Guitarsurfer website