There are instruments that expand what a guitar can do, and then there is the Martin Grand J-28E DN — an instrument that expands what a guitar can be. For the first time in more than a century, Martin has built a double-neck acoustic guitar, and the Interstellar Tone Traveler approaches it with the reverence it deserves: this is not a novelty, not a conversation piece, not a stunt. It is the result of years of engineering, cutting-edge manufacturing technology developed in Nazareth, and a genuine commitment to solving one of the most complex structural challenges in acoustic guitar building — how to mount two necks on a single Grand Jumbo body and produce a balanced, powerful, stage-ready instrument from the result. The dual compound dovetail neck joints and the entirely unique Double Neck X-Brace — a custom DN non-scalloped X with scalloped tone bars developed specifically for this guitar — represent Martin engineering solutions that didn't exist before this project demanded them. The Grand Jumbo body, Martin's most powerful acoustic platform, provides the acoustic real estate and projection needed to support both a six-string and twelve-string neck simultaneously, with solid Sitka spruce over East Indian rosewood back and sides delivering the bold, resonant tone that the Grand Jumbo format is built to produce.

The six-string neck offers a Modified Low Oval profile at 1 11/16" nut width and 2 5/32" bridge spacing — familiar, immediate, and fast. The twelve-string neck is wider at 1 13/16" nut and 2 5/16" bridge spacing, its paired courses opening up the shimmering harmonic complexity and full-bodied shimmer that twelve-string players have always pursued as a distinct tonal universe. Both necks feature satin-finished mahogany, ebony fingerboards with MOP Style 28 inlays, and the same 25.4" scale length — consistent feel across both platforms, just two entirely different voices waiting to be engaged. Custom Fishman electronics make both necks stage-ready without additional gear. Antique white binding, Style 28 back purfling, aging toner gloss top, and nickel open-gear tuners with butterbean knobs anchor the Grand J-28E DN firmly in the Style 28 tradition — classic Martin appointments on the most unconventional Martin instrument in living memory. For the Interstellar Tone Traveler who has always wanted to explore two sonic dimensions at once, the wait is finally over.