Since they can seem confusing to those unfamiliar with the arcane hieroglyphs,
here is a primer of C. F. Martin & Co. Model Designation
The Model Name – two sides of a dash
There are two halves to a typical Martin model designation, with the name separated by a dash.
The first half refers to the “size” or physical dimensions of the guitar, and the second half refers to the visual appearance of the instrument and the materials used to create it, known as the instrument “style.”
REVISED: July 3, 2018
*Note: that statement and what follows does not include the designation “14”, as in D-14, 00-14.
This is a modern invention to denote a 14-fret guitar that a Martin dealer ordered with custom specifications in size D, 00, et al. SEE BELOW*
The body size was originally designated as a number. In staying with customary sizing used by toolmakers and woodworkers, the higher the number on the left side of the dash, the smaller the size of a Martin guitar. Some models introduced in the twentieth century use letters for their size indicator.
C. F. Martin Sr. founded his business in 1833 and was soon offering guitars in sizes ranging from a tiny size 5 on up to a size 1, which that still seems amazingly small by modern standards.
So when they needed a larger size, Martin used Size 0. It was considered large enough for a public concert. Hence the term “concert model.”
As guitarists began to perform in larger halls, alongside banjos and the mandolin, C. F. Martin Jr. offered the 00 in 1873, the same year C. F. Sr. passed away. It was deemed an extra-large guitar for a “grand concert,” and that term has been used to describe guitars of this or similar size throughout the guitar world ever since.
The 000 followed shortly after 1910. It was looked upon as enormous at the time.
All of these sizes were originally traditional 12-fret neck designs, typically employing gut strings. Be they 12 or 14-fret guitars, the most common Martins of the twentieth century can be equated thus:
0 = Concert, 00 = Grand Concert, 000 = Auditorium, 0000 = Grand Auditorium (aka size M,)
OM = shares the same body size as a 000, but typically has other differences.
D = Dreadnought (similar to Gibson’s Jumbo size,)
J = Jumbo (similar to Gibson’s Super Jumbo size.)
Arriving after year 2000 were the Grand J = Grand Jumbo (similar to Guild’s Jumbo,) GP = Grand Performance (similar to Taylor’s Size 14 and the “Small Jumbo” size of many other makers,) and 00L = a 14-fret 00 with Long silhouette due to its “slope shoulders” that are similar to a 12-fret Martin. They were inspired by the Gibson size L guitars, but retain the same depth as other Martin 00 and 000 guitars.
Other builders of guitars have adopted terms like OM and Grand Concert for generic use since the 1970s, typically indicating a 14-fret instrument with a smaller size and narrower waist than the Dreadnought or Jumbo body shapes.
As stated above, “grand concert” originated with Martin’s 12-fret body size of the 1870s. But in its original definition, OM for Orchestra Model actually meant any 14-fret steel string Martin, as opposed to their 12-fret guitars originally designed for gut strings. Initially, the original 14-fret Martins, invented in 1929, were made in the Auditorium size only and given model stamps like OM-18, OM-28. The stamp and model names were changed back to 000 in 1934, when Martin converted all their sizes to 14-fret orchestra models. See below for the differences between modern Martin OMs and 14-fret 000s.
Here are the dimensions of common Martin body sizes available today.
14 Fret – 6 String
|Size||0||00||00 Deep Body||00 Sloped (L00)||000/OM|
|Total Length||38 3/8”||38 5/8″||38 5/8″||39 9/16″||39 13/16″*|
|Body Length||18 3/8″||18 7/8″||18 7/8″||19 7/16″||19 3/8″|
|Body Width||13 1/2″||14 5/16″||14 5/16″||14 3/4″||15″|
|Body Depth||4 1/4″||4 1/8″||4 5/8″||4 1/8″||4 1/8″|
|Grand Performance||0000 (M)||Dreadnought||Jumbo||Grand Jumbo|
|Total Length||40 3/8″||40 5/8″||40 1/2″||40 5/8″||41 1/2″|
|Body Length||19 3/4″||20 1/8″||20″||20 1/8″||21″|
|Body Width||15 3/4″||16″||15 5/8″||16″||17″|
|Body Depth||4 1/2″||4 1/8″||4 7/8″||4 7/8″||4 7/8″|
* Short-scale 000s have slightly shorter Total Length than OM due to shorter neck.
12 Fret vs 14 Fret – 6 String
|Total Length||37 3/4″||39 5/8″||37 7/8″|
|Body Length||19 5/8″||20 9/16″||21″|
|Body Width||14 1/8″||15″||15 5/8″|
|Body Depth||4 1/16″||4 1/8″||4 7/8″|
|Total Length||38 5/8″||39 13/16″||40 1/2″|
|Body Length||18 7/8″||19 3/8″||20″|
|Body Width||14 5/16″||15″||15 5/8″|
|Body Depth||4 1/8″||4 1/8″||4 7/8″|
The instrument Style is also represented by a number. With few exceptions, the higher the style number on a Martin model, the fancier and more expensive are its materials and appointments.
Typical examples of model names include: 000-18, D-28, OM-45.
A 000-18 stands for Size “Triple Oh” (or at the Martin factory, “Triple Naught”) in Style 18, which includes mahogany back and sides, and a top of spruce, with dark bindings on the body, an unbound neck and white dots on the fingerboard, etc.
A D-28 stands for a Dreadnought body in Style 28, which includes rosewood for the back sides, a spruce top, white binding and typically ebony for the fret board and bridge, etc.
An OM-45 is an Orchestra Model size in Style 45, the top of the line for a basic catalog model, which includes top grade rosewood with abalone shell inlaid along the edge of the spruce top, as well as every edge along the back and sides, in addition to fancy, abalone fret markers, and decorative binding on the neck, etc.
In modern times, additional indicators have been added onto some model names.
i.e. 000-18GE 1937, HD-28VS, JC-12-15E. These translate to:
000-18GE 1937 – 000 size in Style 18, with specs designated for the Golden Era Series of vintage reissues, in this case based upon the 000-18 made in 1937.
HD-28VS – Herringbone-trimmed Dreadnought size, in Style 28 with specs of the Vintage Series, using the 12-fret version originally known as the Standard body design. Guitars with the designation H for Herringbone in their name came with scalloped braces, at a time when many Standard Series Martins did not have scalloped braces. Examples include HD-28, HD-35, and the no-longer-made 000-28H. Today, Standard Series 28 models with the H also get the 1930’s style Zig Zag back strip, while those without the H get the later Style 28 back strip.
JC-12-15E*- Jumbo size with a Cutaway body, 12 string guitar in Style 15 with a built-in Electronic amplification system. The designations of 12, C, and E stand for 12 String, Cutaway and Electronics throughout the Martin line, e.g. MC-28, D-18E, HD-28-12.
* Martin never actually made a JC-12-15E. A pity really. I would have bought one if they had.
Designation 14: As mentioned above, “14” when appearing in shops or on line as in D-14, 000-14, etc. means it is a 14 fret guitar ordered from the Martin Custom Shop. It is used the way “Orchestra Model” was once used to mean the 14-fret neck design vs. the Standard 12-fret design.
14 does NOT denote the guitars “style.” Quite the opposite, since it does not give any indication of what wood or non-wood materials were used to build the instrument, what sort of neck joint, neck block, bracing, finish, the instrument has, as would an actual Martin style designation like 18, 28, 45, etc.
It is not unheard of for some merchants to order customized Martin guitars based on various lower-level Series not represented in this article, which are dressed up to appear like higher-end models, and then price them beyond their merits when it comes to what is under the hood, as it were.
When shopping for Martin guitars and you see something listed as a D-14, or OM-14, ask the dealer what was the base model or “starter model” for the custom guitar in question, which will tell you a lot more about the level of quality and construction than may be obviously apparent. If they do not know, they can look it up.
TABLE: Common Styles and How They Vary Based on the Series
Notes: In 2018 Martin released a revised version of their Standard Series specifications, which homogenized certain features, like the shaping of the neck, and the use of forward-shifted bracing on all Standard Series models above Size 000/OM. These models currently have the suffix (2018,) except for the Standard D-28, which has (2017.) I will differentiate the current styles with the same suffixes in the table below.
2018 models with E in the model name come with either Fishman Aura VT Enhance electronics or LR Baggs Anthem electronics, depending on the preference of the specific Martin dealer.
All Standard Series six-string Martins now have the High Performance Neck. This is defined as a Modified Low Oval Profile to the neck shape, and a fretboard with the High Performance Taper, which starts at 1-3/4″ width at the nut and is 2-1/8″ wide at the 12th fret, with 2-5/32″ string spacing. It combines the nut width of Martin’s traditional 1-3/4” necks with the 12th fret width of their traditional 1-11/16” neck, and with string spacing a smidgen wider than that on the old 1-11/16” neck models.
Standard Series 12-string models have a modified version of the High Performance Neck.
Previous Standard Series models had a 1-11/16” Low Profile Neck with 2-1/8” string spacing, except OMs, which had a 1-3/4” Low Profile Neck with 2-1/4” string spacing, and the 000-42, which had a short-scale 1-3/4” Modified V neck, similar to the Eric Clapton models.
All Standard Series Martins have Antique White binding as of 2018, except Style 18 and Style 21, which have faux tortoise binding.
As of 2018, all 0, 00, 000 models in the Standard Series have the 24.9” short-scale neck, while OM, GP, GPC, M (0000), D, J, GJ models have the 25.4” long-scale neck.
All styles have 100% solid tone woods throughout. Style 18 has mahogany back and sides, all others listed below have rosewood back and sides.
|Style||Standard Series||Vintage Series||GE/Marquis Series|
|18||Style 18 was revised in 2016 and currently has genuine Big Leaf Mahogany back and sides, Sitka spruce soundboard and bracing, ebony fingerboard and bridge, mother of pearl fingerboard dot markers, open-backed tuners, tortoise colored binding and pickguard, aging top toner, with an overall appearance reminiscent of Style 18 from the late 1930s.
Forward-shifted, scalloped 5/16” braces on D-18, D-18E (intro. 7/17,) DC-18E, GPC-18E, GP-18E (intro. 7/17.)
Scalloped 1/4″ braces 0-18, 00-18, 000-18, OMC-18E, OM-18E (intro. 7/17.)
Previous Style 18:
Rosewood was used for the fingerboard and bridge from 1940s until the recent return to ebony. Pickguard and binding was black plastic between 1966 until the same makeover, when it returned to tortoise.
Non-scalloped bracing on D-18 and 000-18, each having a 1-11/16″ neck from 1939 to recent makeover.
|The D-18V, OM-18V, 00-18V are now retired, but still common on the used market. They have a Modified V neck profile (the D has a 1-11/16″ width at nut and 2-1/8″ string spacing, the OM has 1-3/4″ width at nut and 2-3/8″ string spacing, the 00 has a short-scale 1-3/4” neck with 2-5/16” string spacing.)
The modern Standard Style 18 has many structural and cosmetic features of the Vintage Series instruments, but with the modern High Performance neck rather than a Modified V neck.
|Example: D-18 Golden Era
Add Adirondack spruce top, 1-3/4” Modified V neck with ’30s Style heel (tubbier overall feel than standard heel,) upgraded tuners, wood fiber inlays instead of plastic, etc.
Golden Era scalloped bracing has more wood removed compared to Standard/Vintage Series scalloped bracing, leading to more flexibility and greater resonance under a lighter attack.
18GE had Brazilian rosewood accents, the later 18 Marquis had Madagascar rosewood accents.
Limited to OM-21 model, and D-21 Special (2017.)
Indian rosewood back and sides, Sitka spruce top.
OM-21 has ebony fingerboard and bridge, faux tortoise binding and pickguard.
The D-21 Special (2017) has Indian rosewood fretboard and bridge, and black binding and pickguard similar to the late 1960s D-21. Only 300 produced.
Both models have white dot fret markers, and Style 18 back strip.
Previous OM-21 1990s – 2012: Indian rosewood bridge and fingerboard with white microdot fret markers, tortoise binding and pick guard. No top purfling or back strip.
Old Style 21 was discontinued in 1969. Typically it had Brazilian rosewood back and sides that were too wild or unusual in figuring to use on the stately Style 28 instruments. At the start of the 14-fret era it had a herringbone rosette and back strip, which were discontinued in the 1940s, when Style 21 became, basically, Style 18 with rosewood for the back and sides instead of mahogany, it traded its ebony fretboard and bridge for rosewood at that time as well. The tortoise bindings and pickguard were switched to black in 1966.
|N/A||00-21GE was a special edition that had features closer to the Vintage Series (Sitka spruce and Indian rosewood, etc.) than the official Gold Era Series models.|
|21 Special||Limited to OM-21 Special and D-21 Special (pre-2017.)
Add many cosmetic features of Style 21 circa 1940, but otherwise a Standard Series OM and Dreadnought model, but made with rosewood bindings, and Spanish cedar necks that lighten up the weight of the guitar and contributes to a more open, airy sound.
Also, they have a 1-3/4″ low profile neck and 2-5/16 string spacing.
(Both models now discontinued but frequently on the used market.)
|28 (2018)||Indian Rosewood back and sides, Sitka spruce top with vintage toner. Ebony fingerboard and bridge.
Antique White binding, herringbone top trim, abalone Diamonds and Squares fret position markers, open back tuners.
Forward-shifted, scalloped braces on all 28 (2018) models.
D-28 (2017) gets large white mother-of-pearl dot markers, forward-shifted, non-scalloped braces.
Previous D-28, along with D-28S (discontinued,) previous GPC-28E, GP-28E (intro. 7/17) have 5/16″ non-scalloped. non-forward-shifted braces.
As of 2018 models with H in the model name, e.g. HD-28 (2018) have the 1930’s style Zig Zag back strip from the Vintage/GE/Marquis Series. Style 28 models that do not have H in the model name get the later Style 28 back strip.
|Higher grade Sitka spruce, Diamonds and Squares fret position markers, grained ivoroid binding, Zig Zag back strip, tortoise pick guard, top herringbone trim, forward-shifted scalloped braces. Modified V neck, with 2-5/16″ string spacing, etc.
Standard Series (2018) adopted many of these features, but not the grained binding or V neck shape.
|Add Adirondack spruce top, 1-3/4” V neck with ’30s heel (tubbier feel overall,) wood fiber inlays instead of plastic, forward-shifted, Golden Era bracing (see Style 18 above.)
|35 (2018)||Indian rosewood sides and three-piece back. Sitka spruce top with aging in toner, and forward-shifted, non-scalloped 1/4” braces, ebony fingerboard and bridge, white mother-of-pearl dot markers, Antique White binding including neck, faux tortoise pick guard, closed silver tuners with large buttons.
OM-35E and HD-35 have scalloped 1/4” braces.
Pre-2018 Style 35 has stark white binding, black pickguard, natural top toner, non-forward-shifted braces.
OM-35 has scalloped braces. HD-35 has herringbone top trim and back strips, scalloped braces, faux tortoise pick guard.
Style 35 first appeared in 1965 and had Brazilian rosewood (until 1969,) and faux tortoise binding and pickguard, which were changed to black in 1966.
“35” has appeared in the model name of several special or limited editions, with woods or appointments different from above. The defining 35 features being a three-piece back and a bound fingerboard.
|40 (2018)||Currently limited to J-40
Same wood grades as Style 35. Indian rosewood and Sitka spruce, forward-shifted, scalloped bracing, 7-ply black and white strip top trim, abalone rosette and small abalone hex fret position markers, bound High Performance neck, Abalone headstock inlay and gold color open back tuners, Style 45 mosaic back strip.
Pre-2018 Style 40 had white binding, 1-11/16” Low Profile neck, non-forward-shifted scalloped braces, black pickguard depending upon year of production. D-40 was basically an HD-28 with fancier pearl appointments and a bound neck. J-40 was also available in all-black finish.
Pre-war Style 40 had short snow flake pattern fret markers and abalone top trim like pre-war Style 42, but no pearl around fretboard extension.
|41 (2018)||Currently limited to D-41 (2018.)
Higher grade Indian Rosewood and Sitka spruce than 28 or 35. Abalone shell trim around top and rosette, but not the fingerboard extension on the soundboard. Abalone hex inlays on neck. Forward-shifted scalloped braces. Aging top toner, Antique White binding, open-gear tuners.
Pre-2018 D-41 had non-forward-shifted braces, natural top toner, white binding. Earlier examples have black pickguards rather than faux tortoise.
D-41 from first year of production (1969) have Brazilian rosewood back and sides. Non-scalloped bracing before 1986.
Style 41 Special – Vintage Style 45 snowflake fingerboard, grained ivoroid binding, forward-shifted scalloped braces (Size D and Size J) and Modified V neck (1-3/4″ neck width on OM-41 Special.)
|42 (2018)||Highest grade Indian Rosewood and Sitka spruce with aging top toner. Abalone rosette and top trim including fingerboard extension. Fretboard has Vintage Style 45 snowflake inlays on fingerboard and bridge, Antique White binding, faux tortoise pickguard, gold-color open gear tuners.
D-42 has forward-shifted bracing, OM-42 has 1/4” bracing.
Pre-2018 Style 42 has grained ivoroid binding, Low Profile neck, 1-11/16” for D, 1-3/4” for OM. 000-42 has 1-3/4” Modified V neck.
|N/A||Limited to 000-42 Marquis (discontinued.) Add highest grade Adirondack spruce top, 1-3/4” Modified V neck with ’30s heel, wood fiber purfling around the pearl trim instead of plastic, etc. Short snowflake pattern on fingerboard. 1/4” GE, scalloped braces.
Vintage Style 42 can be seen on the 2016 000-42 Authentic 1939 with usual Authentic specs (hide glue construction, VTS torrefied Adirondack top, etc.)
|45 (2018)||Currently limited to D-45.
Highest grade Indian rosewood and Sitka spruce. Abalone trim on all edges of top, sides and back, hex inlays on neck, etc. Abalone hex fret markers. Forward-shifted, scalloped braces, Antique White binding, gold color open gear tuners, faux tortoise pick guard.
Pre-2018 Style 45 has white binding, natural top toner, non-forward-shifted braces, 1-11/16” Low Profile neck.
Earliest modern examples (1968-69) had Brazilian rosewood and European Alpine spruce tops, changed to Sitka shortly thereafter, Indian rosewood from 1970.
Black pickguard replaced with tortoise in recent years.
|Add Modified V neck, pre-1938 Style 45 snowflake fingerboard pattern, grained ivoroid bindings, vintage top toner, tortoise pick guard, forward-shifted scalloped braces.
Style 45 (2018) adopted much of this styling, except fret markers, binding, and neck shape and size.
|Same as Vintage Series, but add highest grade Adirondack spruce top, 1-3/4” Modified V neck with ’30s style heel, wood fiber purfling around the pearl trim instead of plastic, Golden Era scalloped bracing (see Style 18 GE above.)|
Note: specs listed are only notable examples.
* Authentic Series not included in this table. Each Authentic model is as as-close-as-possible recreation of a specific Martin guitar from a specific year. Examples include D-18 Authentic 1939, OM-28 Authentic 1931, 00-18 Authentic 1931. See more specific reviews HERE.
** The Golden Era Series was introduced after the Vintage Series, to offer more-accurate vintage reissues, which included the use of Adirondack spruce and also Brazilian rosewood as back and sides on Styles 28GE and 45GE and for cosmetic trim on Style 18GE guitars. Prior to the official series getting under way, a version of the D-18GE was made with a Sitka spruce top, as was a 12-fret 000-28GE.
The Marquis Series was introduced after the shortages of Brazilian rosewood halted GE production. Marquis guitars are basically identical to GE models, except for the substitution of Brazilian rosewood with Indian rosewood on 28 Marquis and 45 Marquis, as well as Madagascar rosewood as trim on 18 Marquis. Some additional, minor changes occurred over time, like the brand of tuning machines, etc.
Surviving members of the Vintage Series, Golden Era Series, Marquis Series, are currently found with the Authentic Series under the umbrella of Martin’s “Vintage and Authentic Series.”
Just the Facts
Q: Why are there many numbers missing among the Martin Style names?
A: Some styles have gone extinct. The earliest Martins were made in a variety of sizes and cosmetic trim. At one point, Mr. Martin matched one body size with one style of trim. Each was assigned a specific price. A guitar in Size 1 cost $17 and became known as Style 17.
Once prices began to rise, the original Style names stuck, but were associated with the specific trim rather than the price. These set trim styles eventually began to appear on different sizes. Old C. F. died in 1873 but his son and grandsons continued to use and expand upon his methods. By 1900 the current system of Size on one side of the dash and Style on the other was well in place.
Some Style numbers that were gone by 1950 have been resurrected, but with cosmetic specs or woods that are different from their original version.
Example: Style 17
Style 17 had Brazilian rosewood back and sides and a spruce top in the 1800s. It was changed to mahogany back and sides circa 1906 and was retired in 1918, when Style 18 was switched from rosewood to mahogany.
Style 17 was reborn in 1922, in all mahogany (including the top,) with a satin finish (similar to today’s Style 15, which only existed as the 0-15 with a spruce top until 1940, when it was given a mahogany top.)
Style 17 was made in smaller and smaller numbers until retired in 1961 (with a one year resurrection in 1967.)
It returned again as a fancier version of modern Style 15, with white purfling and a high-gloss finish, before being put to bed yet again.
More recently, Style 17 was revived as basically a 15 Series guitar with a spruce top instead of mahogany, and with a reddish finish tint and sunburst top in a 14-fret Dreadnought size and a 12-fret 000, the 000-17S. Those have since been retired.
In 2016 three new sizes were offered in Style 17 (the 12-fret 00, 14-fret 00L, and 14-fret 000), with two new cosmetic packages, the Black Smoke (all black with white trim and pickguard) and Whisky Sunset (bronze-orange to black sunburst.) And Style 17 is now re-positioned as Depression Era budget guitars made of all solid wood for players looking for a great value with a spruce top.
More details about Martin model designations
When compared to current designs, Martins prior to 1930 were similar to modern, Classical guitars in many respects, all having an elongated shape with a wide 1-7/8″ neck that offered only 12 frets clear from the body and top braces intended for gut strings. In fact, Martins were the preferred choice for American concert professionals performing the classical repertoire in the decades between the Civil War and the Second World War.
Martins moved into a position of prominence in popular, country, and folk music once their 14-fret steel string guitars appeared during the Great Depression. Andre Segovia’s tours of the US during the 1930s and ’40s shifted Classical guitar firmly toward guitars that evolved in Spain at the same time Martins were evolving in America.
Martin shifted their own focus toward steel strings during the early twentieth century, but other than their Hawaiian-style guitars meant for playing with a steel slide, they did not design guitars specifically for steel strings until the OM, which first appeared in the 1930 catalog.
The Orchestra Model was the first Martin guitar to break with the numbered size convention, when its model stamp on the neck block was represented by the initials OM. The new design featured a 14-fret neck and a body braced exclusively for steel strings. The new name was meant to attract members of dance orchestra rhythm sections, who were switching from the banjo now that steel strings were becoming the norm for acoustic guitars.
Although some Jazz musicians played the new steel string Martins, it was actually pop music icons singing in front of bands on the new sensation of radio, like Gene Autry and Roy Rodgers, who embraced the revolutionary guitar design. In later years it was traditional Blues soloists, and eventually New Age fingerstyle guitarists who took the OM into ever expanding genre of guitar music.
Because the OM and the 14-fret 000 share the same body size, there is often confusion about how their modern examples differ and why. (See below for more information about that.)
D – Dreadnought
Other model names without numbers include D for Dreadnought. These are the large, now iconic guitar shapes that Martin invented in a 12-fret size in 1916, exclusively for the Ditson musical department store chain, which intended them to be used as the “bass guitar” in mandolin orchestras.
Dwarfing all other sizes at the time, Dreadnoughts were named after the British battleship H.M.S. Dreadnaught (sic), but also as an insider joke. Their largest sizes were the Naught, Double Naught, and Triple Naught. This new size was the biggest Naught of them all.
Martin first offered a dreadnought sold under their own brand name in 1931, and three years later, a 14-fret version was released as well, which became the most popular steel-string guitar design in history. For example, the memorable acoustic guitars played by Johnny Cash, Neil Young, Nirvana’s Kurt Cobain, and Coldplay’s Chris Martin are Martin dreadnoughts.
M or 0000 – Grand AuditoriuM
The M size was introduced in the 1970s. It stood for Grand Auditorium and at times is referred to as the 0000, or Quadruple Oh/Naught. It is a flattop guitar that uses a body shape taken from the mold of a Martin archtop model made during the Jazz Age. They actually used the molds from the 1930s to make the sides.
At its introduction, the M had the widest Martin top, matched with sides having the depth of an OM. Ms are known for their even balance, sounding similar to the Dreadnought but with the bass pulled back in line with the other registers.
J – Jumbo
The Martin Jumbo was the brainchild of C. F. Martin IV, the current CEO. It combines the depth of a dreadnought with the shape and top width of a Jumbo. To my ear it sounds like a super-sized 000, with balance across the registers, but with considerable volume, and a focused, punchy midrange.
GJ – Grand Jumbo
Like the M, the Grand J takes its body from an archtop, only this time it was Martin’s modern Jazz guitar, the CF-1. But after some prototype examples, they altered the exact shape a bit. It has a 17” wide lower bout, the widest flat top Martin has ever made. The Grand Jumbo has only been around a few years. It has appeared as normal 6-string and 12-string models. But it has also been used on limited edition baritone models, designed with a longer neck for lower tunings.
GP – Grand Performance
The company’s first totally new flat top body size in many decades. With a top slightly wider and rounder than an OM and a deeper body, they are Martin’s version of the “small jumbo” models that have grown in popularity in recent years. While Gibson’s J-185 from the 1950s might be considered the first true small jumbo, it was in the 1980s that indie luthiers Kevin Ryan created the design associated with the term today, while a similar design by James Olson was most responsible for small jumbo’s surge in popularity among professional artists. But Taylor’s Size 14 design is what got it into the hands of the common guitar player. And Martin’s GP with a cutaway is almost identical to the Taylor design in terms of dimensions, even if they do not sound much like a Size 14 Taylor. In general, GPs sound like an OM with a more pronounced bottom end, and with greater volume.
00L – Slope Shoulder Grand Concert
The 00L (L for Long) size debuted in 2014 with the CEO-7, which was designed by C. F. Martin IV as a nod to Gibson’s fabled L00 guitars of the 1930s. After a couple of limited edition CEO models that combined Martin’s original slope shoulder dreadnought shape with a 14-fret neck, he decided to put the elongated slope shoulder shape on a short-scale 14-fret 00, creating a smallish guitar with a slightly larger sound chamber than the normal 00, increasing bass response. It was a sensational success. The more affordable 00L-17 followed in 2016.
Now back to the OM – 000 confusion…
To make the revolutionary OM, Martin turned to their Standard 12-fret 000, which was the largest size they offered in 1929. Basically, they squashed the slope shoulders down almost flat, which exposed two more frets and pushed the upper bout farther out. This also had the effect of placing the bridge closer to the neck, relative to the overall body length.
Then they narrowed the neck from 1-7/8″ to 1-3/4″ for the target audience of banjoists and added bracing designed to work best with the tensions of steel strings … and viola! They invented the modern, flat top acoustic guitar.
After three years, it was clear Martin was going to convert the bulk of their catalog to the new 14-fret steel string design, so the OM stamp was replaced with 000, sometime in the early months of 1934. This allowed them to get back to their traditional numbered sizes. The 12-fret versions were retired, with a few exceptions, like the 00-21. And some dealers did order the occasional 12-fret Martin otherwise. But the future clearly belonged to the 14-fret Orchestra Models.
At Martin, at least, any guitar made from that point on with the 14-fret design was an “Orchestra Model.” In fact, during the first years that the 14-fret dreadnought was offered in the Martin catalog, it was listed as “Orchestra Model, Size-D”.
Guitars that retained the elongated body and 12-fret neck were referred to as Standard models, and in modern times an S is added to their neck block stamp for “Standard.” This is sometimes confused with guitars made up through the 1950s that had an S added for “Special,” typically meaning some sort of customized Martin guitar from before they had an official custom order policy.
The 14-fret 000s made in the first months of 1934 are identical to the OMs made in 1933. But soon after, changes were instigated in the design. It is my belief that this was due to the tension from steel strings on a relatively narrow, long-scale neck causing too many repair issues. The first major change was having the string scale shortened by half an inch, equal to that on 14-fret 0s and 00s.
The new, short-scale 000s also has their tone bar braces increased from 1/4″ to 5/16″. It remains a question of history as to exactly which came first, the change to 5/16″ tone bars, or the short-scale neck, or if they arrived at the same time.
All 14-fret Martins went to a narrower 1-11/16″ neck in 1939 and the company stopped using scalloped bracing in 1944 (Actually this was transitional, as 1945 Martins have what is now called tapered bracing.)
So, by the mid ‘40s the 14-fret 000 had an auditorium body size and a short-scale neck like the 0 and 00 sizes, but with bracing of the size and density found on the larger dreadnoughts.
The Martin 000s of the 1950s and 60s continued this overall design, as they stood up well to the thick flat picks and steel fingerpicks popular at that time, and fit into group playing, as the guitars’ punchy notes could cut through an ensemble without upstaging other instruments.
The Modern OMs
Starting in 1969 Martin answered the call for guitars made in the tradition of the original OM-stamped guitars, with sporadic special editions. The “OM” became an official model type in 1990, which has the same shape as the 14-fret 000. But otherwise, several differences separate the two designs.
The traditional 14-fret 000 had evolved to have a narrow, short-scale neck and 5/16” non-scalloped bracing.
Modern OMs have a wider, long-scale neck and 1/4” scalloped bracing. (The OMs made in the 1930s actually had a center X-brace that was 5/16,” surrounded by 1/4” tone bars.)
The lines dividing the 000s and OMs have since blurred, due to all the vintage reissue models and limited editions that have come out in the past 25 years.
Traditional 000 necks have the short scale, while 000s below Style 18 have a long-scale neck, since that is now the industry standard. But the new 2016 000-17 has returned to the short scale neck and also acquired the modern High Performance neck. Martins shall ever and always continue to evolve.
Vintage-style 000s often have a 1-3/4” neck, like the Eric Clapton models and the pre-2018 000-42. The modern 000-18 and the 000s from the Marquis/GE series also have 1/4″ OM-style bracing to help make them sound like the lighter, more resonant 000s from the 1930s. This is partly because modern guitars are made with thicker wood and finishes to withstand the rigors required of a lifetime warranty.
Some Limited Edition/Custom Artist OMs, like the John Mayer and Paul Simon models have necks narrower than 1-3/4” and so on.
To confuse matters more, as of 2018 most all OMs and 000s have been converted to the modern High Performance neck. It has a 1-3/4″ width at nut, but the overall neck is closer in width and string spacing to a traditional 1-11/16″ Martin neck. It is just cheated a bit wider down in the “cowboy chords” area below the 5th fret.
Despite the many exceptions, it is safe to say that typical Martin OMs have lighter, scalloped bracing matched with a long-scale neck that has a 1-3/4” width at nut. Any other defining characteristics depend greatly on the specific year or era of construction.
OMs are recognized today by their small, roundish pick guard, often called a “tear drop,” even though the original OMs from the 1930s switched to the longer Martin pick guard about six months into production.
How do they sound? To my ear a typical 000, with 5/16” bracing, has a focused, punchy voice that cuts well as a lead guitar but on the whole is a more intimate instrument.
The OM has different dynamics leading to a different kind of voice. With its lightly braced top matched with the string tension of a long-scale neck, the OM has a more open voice with greater fundamental note separation, a wavering resonance and greater projection, sounding clearer farther away than a 000, which can sound just as loud as an OM to the guitarist, but drops off over distance. Overall, it has a lot more going on behind and around the top voice (fundamental string notes and high harmonics,) while the 000 puts most of the energy and sound into that fundamental top voice while the undertone plays more of a supporting role.
But compared to other sizes and types, Martin OM and 000 remain closely related in look, feel and tone. They are famous for having a more-perfect balance to the volume of each string, compared to all other 14-fret guitars.
This quality is also the hallmark of the 12-fret 00 and the 12-fret D sizes, even though the dynamics and volume vary greatly between the three designs.
Read More at: Martin’s 000 vs. OM, What’s the Diff?
And that is one man’s word on…
Martin Model Designation
Note: This illustration dates from the late 1980s most likely. The MC is shown with the deeper cutaway that was used on the original design, which had an oval soundhole. The Jumbo size is not listed but it has the same silhouette as the M. Sizes SJ, GP, and 00L were introduced in the twenty-first century.