Martin 000 vs OM, what’s the difference?

A reader seeks help understanding why Martin 000 guitars in the lower price ranges are not called OM.

I really enjoy the site. Especially the information about Martin Guitar.

Can you help me better understand why Martin uses the “000″ (triple aught) designation for orchestra bodied models below the 18 Series, when “OM” would be a more accurate designation since they have a standard length scale?


Jim in Pennsylvania

Spoon writes:

Hi Jim,

Thank you for your kind words and interesting question.

I am going to answer your question, and then use it as a spring board to address the whole 000 vs. OM issue.

The simple answer to your actual question is, the 25.4″ string scale, known as the “long scale,” became the industry standard for guitars with that body size, so Martin decided to go with the long scale for the sake of direct competition. And the name of “000” for that size was more well known generically than “OM.”

In terms of traditional 000s vs OMs, the 000s from the late 1940s on up until modern times recently were made with a short-scale neck that was 1-11/16″ in width at nut, with non-scalloped 5/16″ bracing. The OMs, which did not exist between 1934 and 1969 (and did not appear in the main Martin line until 1990) have a long-scale neck, which makes them louder and more powerful, and 1/4″ scalloped bracing that makes them more resonant with greater projection than a comparable 000. That remained the case with all guitars made in Style 18 and higher until quite recently.

Also, at the time this decision was made to offer the lower-priced Martin 000s in the long scale, there were actual OM models offered in Style 16 and Style 15, as well as the Road Series and 1 Series. OMs typically differed from 000s in various ways other than scale length, even though they shared the same dimensions in terms of body size.

Over the years the lines between the two designations have merged, until it seems arbitrary as to why one guitar is called 000 while a similar guitar is called OM.

But, as usual, the facts leading up to it all are not so simple.

For those who might need to know, the “scale” we are referring to is the length of the string from the saddle to the nut, i.e. the part of the string that is played and fretted to make music. The longer the scale, the more string tension and resulting resonant energy, but the wider the space between each fret on the neck.

And it may be helpful to remind folks that acoustic guitar sizes tend to follow this system:

Concert (Martin size “0”)

Grand Concert (Martin size “00” – similar to Gibson size “L”)

Auditorium (Martin size 000 or size OM)

Grand Auditorium (Martin size 0000 aka size M)

Dreadnought (similar to Gibson’s round shoulder Jumbo size, and their square shoulder guitars like the Dove, and Hummingbird)

Jumbo (similar to Gibson’s Grand Jumbo)

Grand Jumbo, aka Grand J (similar to Guild’s Jumbo)

This brief history lesson should help clear up some of the confusion surrounding the whole OM vs 000 conundrum.


From the company’s founding in 1833 up to this point, Martin only made 12-fret guitars with rounded shoulders, similar in shape and look to modern Classical guitars, even though they typically had steel strings by this time. The largest size sold under the Martin brand was the 000. (The mammoth dreadnought size was made only for the Ditson department store, beginning in 1916.)

In late 1929, Martin made a special auditorium-size guitar with a longer neck, for popular band leader Perry Bechtel who wanted to transition from the banjo to the steel string guitar. Basically, they flattened down the shoulders on their standard body shape, which spread them wider while exposing two more frets for playing.

That guitar became the prototype of Martin’s revolutionary Orchestra Models, which were the first Martins designed from the ground up for steel strings, and which offered 14 frets clear from the body. In other words, they were the first modern acoustic guitars, with a direct influence on almost every flattop acoustic guitar that followed.


Martin’s catalog offered for sale the new 14-fret guitars in their largest size, the 000, but the model stamp inside the guitar had the 000 replaced with “OM”, as in OM-18, OM-28, OM-45. The name Orchestra Model was a marketing ploy meant to attract bajoists in dance orchestras.

Most people do not know that Martin also offered the 1930 0-17 in the 14-fret orchestra model design as well. However, it did not get the OM as part of the model stamp.

But it is the actual OMs that matter here…

The OMs of that time went through a rapid evolution. For example, the small pickguard only lasted some six months (although some examples from 1931 exist.)

The straight bridge used for decades at Martin was replaced with a larger belly bridge.

The bracing on the original OMs consisted of an X-brace that was 5/16″ in width, surrounded by smaller “tone bars” that were 1/4″ in width.


The Ditson department store closes during the Great Depression, Martin offers the Dreadnought body size under their own brand for the first time. The D-1 and D-2 are sold as test models and then quickly become the D-18 and D-28. Both have the 12-fret body design.


Martin introduces a 14-fret version of ALL their sizes from 0 to the D. Any 14-fret Martin is considered to be an “orchestra model,” as opposed to the 12-fret “standard models.” For example, the 14-fret dreadnoughts appear in the 1934 catalog as “Orchestra Model, Size D.”

Martin changes the stamp inside the OMs to “000” so they may return to their normal size designations. Therefore, a 1933 OM is identical to a 14-fret 000 from early 1934. They are the exact same thing.

Sometime during the first six months of 1934, Martin changes the 14-fret 000s to the short scale already used for the 0 and 00 sizes, leaving the dreadnoughts as the only long-scale Martins. And the bracing on the 000 changes to 5/16″ for all braces, around the same time. Long-scale 000s from 1934 remain among the most desirable Martin guitars.


Martin changes their neck width for all 14-fret models from 1-3/4″ at the nut to 1-11/16″ and changes the string spacing accordingly.


Martin changes all bracing to non-scalloped “straight” bracing. (Actually, this evolves starting in 1944.)

So, by this time, all 000-size Martins are short-scale guitars, with a 1-11/16″ neck and 5/16″ non-scalloped braces. This 14-fret 000 design remains in place for the next 60+ years.


A guitar shop in Pittsburgh convinces Martin to make a small batch of “OMs” that have a long-scale 1-3/4″ necks. This was Music Emporium, which moved to Massachusetts in 1970.


By 1970 the only 000s remaining are the 000-18 and 000-28.

Various small-shop luthiers begin to offer guitars closer to the old Martin OMs for fingerstyle guitarists. Martin remains conservative, offering OMs in small limited editions throughout the 1980s. They have 1/4″ scalloped bracing, to better simulate the lighter, more responsive build of the 1930s Martins.


In 1990, Martin finally introduces the modern OM into their main catalog. The guitar has the same body size as the 000, but it has a long-scale, 1-3/4″ neck with compatible string spacing, rather than a short-scale, 1-11/16″ neck. OMs continue to have scalloped 1/4″ bracing, while 000s have straight 5/16″ bracing.

The OMs are also offered with the smaller “teardrop” pickguard similar to those seen on the earliest OMs from 1930.

By the end of 1994 the modern, Standard series OM-28 and OM-45 have come and gone, but the OM-21 and eventually the OM-42 take their place.

In 1996 the OM-28V enters the new Vintage series of Martin guitars, offering even more vintage-esque features, like wider string spacing and a V neck shape. The OM-18V and OM-45V soon follow.

As for 000s, the introduction of the Eric Clapton models in the early 90s provide short-scale 000s that have 1-3/4″ V necks and scalloped 5/16″ braces.

Sometime around the turn of the century, Martin expands their more affordable series of guitars, below Style 18, and the decision is made to offer all such 000s in the long scale, which has become the industry standard. The first major blurring of the lines between OM and 000 appears.

The OMs below Style 18 continue to have a wider neck and thinner braces, but scalloped braces and a long-scale neck have finally come to the contemporary 000s. Yet the Standard series 000-18 and 000-28 retain the short-scale neck and straight 5/16″ bracing.


All heck breaks loose.

OMs below Style 18 go extinct, leaving only long-scale 000s.

The Golden Era/Marquis series of Martin guitars introduces the 000-18GE and later the 000-42 Marquis. Both guitars offer 1/4″ scalloped OM-style braces on a short-scale 000.

The John Mayer signature model offers an OM with a 1-11/16″ neck, and the lines between OM and 000 continue to blur further.

Please bear in mind there are exceptions to almost everything I have said so far, when it comes to limited editions, special editions, artist signature models, etc.

To make matters more confusing, Martin recently decided to put their new “high performance” neck on their Standard series OM-21 and 000-18, so they now have the same neck and string spacing. The neck has a 1-3/4″ width at the nut, but basically has the dimensions of the 1-11/16″ neck, only cheated out a bit wider near the headstock.

At least the 000-18 (and hopefully soon the 000-28) gets the scalloped 1/4″ braces it deserves, while it remains a short-scale guitar. And the OM-stamped guitars continue to have a long-scale neck and 1/4″ braces.

All in all, it is easy to see how someone would look at the current Martin lineup and wonder; why would a long-scale Auditorium-size guitar made in the various series below Style 18 be called a 000 rather than an OM?

When it comes to Martin guitars, the answer is rarely as simple as the question.




We and our readers would very much like to hear what YOU think.

This site uses Akismet to reduce spam. Learn how your comment data is processed.