Over the course of her recordings leading up to third album Nepenthe, Brooklyn-based solo musician Julianna Barwick's vaporous compositions were largely the product of infinite layers of her own voice, looped and processed into misty, near-cosmic realms.

Spreading out across a wide range of octaves, her mostly wordless vocalizations found a specific state of emotional transparency that could instinctively communicate by turns feelings of harrowing darkness, contemplation, fear, and confusion -- or even an understated humor.

No small feat, being able to say so much without any conventional language, and Barwick pushed her atmospheric songs to new places, adding subtle layers of guitar and piano to her walls of voices on 2011's The Magic Place.

With Nepenthe, the depth of her sound expands even further, including more collaboration and experimentation than ever before, without ever losing the direct approach that guided her earlier work.

The album was recorded in Iceland with longtime Sigur Rós producer/collaborator Alex Somers, and the same dreamlike shards of glacial production that have enhanced Sigur Rós' best efforts come through here as well.

With most of her other albums being recorded in practice spaces or bedrooms, Barwick has never been afforded the spaciousness her billowing vocal loops suggested and at times artificially replicated.

Here, with the benefit of cavernous room sounds and natural reverb and delay, each vocal track gets a little more character of its own, dialing the layers back somewhat since each offers more by itself.

Tracks like "The Harbinger" and "Labyrinthine" replace what once would have been more of the same voice with both haunting piano lines and the incredibly placed addition of an Icelandic girl's choir.

"One Half" sounds almost pop compared to Barwick's previous work, including the closest thing to a discernible English lyric, repeating over cinematic drums and brittle strings.

While the heightened production brings a vividness and depth to the album, the advances in songwriting and arrangement are what's truly striking on Nepenthe.

While still coming from a deeply insular place, the expanded instrumentation and collaborative element put Barwick in the role of conductor, opening up her very personal song worlds to a supporting cast.

While comparisons to the icy beauty of Sigur Rós, the ethereal curiosity of Cocteau Twins, and any number of new age reference points are inevitable and warranted, Nepenthe shows a much deeper side to Barwick's art.

In the same way Eno's ambient work was as detailed as it was static, Barwick directs Nepenthe like a slowly unfolding film, burying an arc of storytelling and exploration inside what could just as easily pass by unnoticed.

It's not only her biggest and most ambitious production to date, but also the album that best showcases her gift for communicating complex emotional entanglements so simply and clearly they become almost weightless.