Dreadnought (guitar type)

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 (1906) 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 (in its most popular configuration) square shoulders and bottom. The neck is usually attached to the body at the 14th fret.

Martin dreadnought guitars are 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. Size "D" represents (effectively) the largest in the Martin range, smaller sizes being (in decreasing order), 000/OM, 00 and 0; historically (pre-1900 or thereabouts), even smaller sizes were produced including 1, 2, 3, 4, etc. 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.

History
Prior to around 1900, Martin acoustic guitars were available in sizes that to today's players would seem very small, ranging from size 5, 4, 3, 2 1/2 and 2 (all 12 inches or less across the lower bout) to size 1 (12 3/4 inches). Larger sizes, introduced by 1898, were size 0 (13 1/2 inches), size 00 (14 1/8 inches), size 000 (15 inches) and, subsequently, the 12-fret D plus its successor, the 14-fret D (both 15 5/8 inches). In fact, the first model to be produced in the "dreadnought" size was the largest of several models manufactured by Martin for the Oliver Ditson Company; of the nine models catalogued (1, 11, 111; 2, 22, 222; 3, 33, 333) the 111, 222 and 333 shared the large (dreadnought) dimension and differed only in the degree of ornamentation. (Although catalogued, it seems that no "333" Ditson models were listed as produced, although some may have been). These guitars were produced by Martin for Ditson from 1916 to 1921; a small number (19 instruments) were subsequently made in the same style as the 111, in dreadnought size, between 1921 and 1930, including #19734 for Roy Smeck. According to Mike Longworth, the design for the "111" size, later to become famous as the dreadnought, was suggested to Martin by Harry L. Hunt, the then manager of the Ditson New York City Store, and "most likely" prototyped by Martin employee John Deichman. Up to 1923, it appears that the early dreadnought-size guitars constructed by Martin were fan braced, not X-braced, that innovation being first combined with the "dreadnought size" body in 1924.

In 1931 Martin began producing dreadnought guitars (sometimes also spelled "dreadnaught") under its own name, 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 neck position (the neck was moved outwards a little from the body, resulting in a slightly altered bridge placement relative to the lower bout)—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.

Early in their production (e.g. between 1931 and 1934), Martin seems not to have had much faith in these "extra large" guitars, making them only on special order (even the "000" size was considered large by the standards of the day) and to one interested customer writing in 1933 that the firm considered the dreadnought "a bass guitar, not suitable for solo playing". However perceptions changed when the then hugely popular Gene Autry, singing star of stage and screen, wanted a new guitar, of style 45 (Martin's most ornate) and ordered a custom instrument of that style in Martin's new, largest size. Thus, the D-45 was born, Autry's 12-fret example being the first, and soon other country singers on particular wanted the large size instruments, which proved effective in sound carrying power (particularly for vocal accompaniment) over the otherwise primitive stage amplification systems of the day.

The 1936 Martin Catalog lists only 2 dreadnoughts, the D-18 at $65.00 (approx. $1,445 in 2024 dollars) and the D-28 at $100.00 (approx. $2,223 in 2024 dollars), although the D-45 was also available at that time to special order only. A later 1930s catalog does include the D45 at $225.00, by which time the prices of the D-18 and D-28 had increased to $75.00 and $115.00, respectively.

The popularity of, and demand for, Martin dreadnought guitars was increased by their use by folk and popular musicians of the mid-20th century, such as Paul Simon, Joni Mitchell, Crosby, Stills, Nash and Young, and Van Morrison as well as in the early rock and roll field by artists such as Elvis Presley. Having to compete with intrinsically loud instruments such as the 5-string banjo, often in generally "acoustic" settings, dreadnoughts also became the standard guitar of bluegrass music, and were 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. Guild also offered "dreadnought" size guitars from 1964 onwards, their D-40 and D-50 offerings (in mahogany and rosewood bodies, respectively) closely paralleling the Martin D-18 and D-28, and being described as "Guild's improved version of the popular dreadnaught guitar".

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

Commencing in the 1980s, Martin has produced its models "M" (sometimes known as 0000) and "J" which are in fact wider than the "D" shape in upper and lower bouts, but enclose less volume of air on account of a narrower waisted design plus a body depth that is shallower than the dreadnought. These instruments were intended to combine some of the volume characteristics of the dreadnought with less of the pronounced bass response of the latter, and are basically production versions based on a guitar owned by David Bromberg that used the body of an old Martin F-7 archtop guitar converted to a flat-top by Matt Umanov in the 1960s, in combination with a D-28 style neck.

Up to approximately the mid 1970s, dreadnought guitars from Martin, the original maker, were available in a fairly basic set of model styles, comprising the "D" designation for body size, plus the numeric designation—drawn from the range 18, 21, 28, 35, 41 and 45—indicating the degree of ornamentation, and wood used for the body construction (custom models were also sometimes available upon request); the D-45, however, was out of production between 1943 and early 1968, in which year it was re-introduced to the Martin line, while the D-35 was a new model and style designation, introduced for the first time in 1966. By contrast, in more recent decades the range has grown massively; a 2024 query to the Martin website yields 170 varieties of 14-fret dreadnoughts (including discontinued models) plus a further 6 12-fret models (and this list is not complete). Further information on these instruments is available on the website of the manufacturer and of various resellers, while other stores such as Gruhn Guitars and Carter Vintage Guitars offer a glimpse into the world of vintage and/or collectable guitars, the most valuable of which are frequently Martin dreadnoughts from the classic "pre-war" (pre 1942 in collector's terminology) manufacturing period.

Internal construction
Martin dreadnought guitars feature the 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.