Though recent indie rock groups have relied heavily on the choral sound of multi-track vocals—Fleet Foxes, Grizzly Bear, and Sufjan Stevens to name a few—none of them have done it quite as impressively as Bon Iver in “For Emma, Forever Ago,” the 2007 debut album written, performed, and produced by Wisconsinite Justin Vernon. Part of the success of the album was the stark and at-times haunting instrumentation that supported his hymnal voicing.

In Vernon’s newest project, an entirely new musical setting from the one established in “For Emma” surrounds these same vocal styles, yet it is just as moving. “Unmap,” is a collaboration with the Milwaukee-based instrumentalists Collection of Colonies of Bees (CoCoB), released under the name Volcano Choir. Though the experimental tracks lack direction at times, the music on “Unmap” blends the sounds of the two bands seamlessly, combining the heartbreaking backwoods emotion of Bon Iver with the textural, ephemeral hooks of CoCoB into an album rich with surprise and intimacy.

A clear example of this inherent synergy is the song “Still,” which is actually the Bon Iver song “Woods”—off January’s “Blood Bank” EP—accompanied by numerous synthesizers, guitars, and loops. The original is comprised solely of Vernon singing one melodic line, laced with Auto-Tune, repeated over and over, each time with an added harmony layered on top. While this works nicely, the beefier version on “Unmap” is a hypnotic masterpiece that retains the eeriness of Vernon’s melody while adding a powerful and expressive eclecticism, courtesy of CoCoB.

On “Still,” the distinction between Vernon and CoCoB’s contributions is clear, but on “Island, IS,” Volcano Choir prove that they are indeed one cohesive band. The track centers on a mesmerizing guitar and synth riff, enforced by tropical and free-spirited percussion. Vernon’s impassioned harmonies and falsetto fit skillfully on top of the rhythmic loops. The light-heartedness of the instrumentation makes the pathos inherent in Vernon’s voice less grounded, resulting in a track that is simultaneously light and catchy yet deep and moving.

The album emerges an intriguing and surprising experiment. Several of the songs are so freeform that they progress along an undetermined path, ending with little resolution or warning.

The opening track, “Husks and Shells,” begins with acoustic guitars tuning and warming up in the distance. Eventually, the guitars settle on a melody, but never on a rhythm, and the melody is repeated erratically. In the distance, a faint metronomic beeping and various guitar notes are delicately enhance the natural vibe.

In between the seemingly improvised guitars is Vernon’s ethereal humming floating softly above. It sounds genuinely like what the first collaboration must have sounded like; the guitarist warming up in the corner and Vernon slowly taking notice and tenderly joining in, neither of them knowing where it was going, what to do next, or how to stop it.

The sense of surprise inherent in “Unmap” is found not only in its painterly collection of noises, but also in the talents of Vernon as a singer and songwriter. It is almost shocking to hear how well the vocals and music in Volcano Choir fit together.

This new, more colorful musical setting has the power to alter the passion inherent in Vernon’s vocals and vice versa. “Unmap” seems to prove that even estranged from the broken-heartedness of Bon Iver, Vernon’s music is still stirring.