Martin Custom Shop OM Auditorium 28 Style Acoustic Guitar, Adirondack Spruce/Sinker Mahogany

The Martin Custom Shop “OM” Auditorium is built on a blueprint that helped shape the American acoustic guitar as we know it. Originally introduced in the early 1930s, the Orchestra Model (OM) combined a 25.4" long scale with a 000-size body, creating a platform that became a staple for fingerstyle players, session musicians, and soloists alike. This particular Custom Shop build updates that formula with both subtle refinements and choice materials hand-selected through Martin’s long-standing partnership with Russo Music as an Expert Dealer.

The body features a bound Adirondack spruce top paired with Russo Music–selected premium sinker mahogany back and sides. Adirondack has long been favored for its high stiffness-to-weight ratio, while sinker mahogany, recovered from riverbeds, has earned a reputation more for its provenance than any unverifiable tonal mythology. The 1/4" Golden Era scalloped X-bracing (also Adirondack) is forward-shifted, offering a structural design historically associated with pre-war Martins.

The neck is carved from select hardwood and shaped to the GE Modified Low Oval profile with a High Performance Taper. This design balances vintage shape with modern playability. A long diamond volute nods to Martin’s legacy neck construction. The ebony fingerboard features a 16" radius and is adorned with Diamonds and Squares Long in abalone—a high-end twist on the traditional 28-style aesthetic. Standard 20 frets and a 1 3/4" bone nut round out the specs.

There’s no onboard electronics, a decision that reinforces the purist build philosophy. The finish pairs an antique toner top with a gloss body and satin neck, giving this OM both presence and playing comfort. Herringbone top inlay, HD Zig Zag purfling with black accents, and Grover open-gear tuners complete the visual and functional package.

This guitar is a reflection of what the Martin Custom Shop does best: honoring tradition while executing each detail with precision. A Custom Shop OM from a shop that knows the difference.