Julianna Barwick's previous album, the critically acclaimed The Magic Place, was always going to be a hard act to follow. When you can make such an impressive piece from a palette that essentially consists of only heavily reverbed vocals and loops, the temptation must be to just keep doing that for every album, or just stop, happy in the knowledge that you have gone as far as you can within that realm.

On the follow-up Nepenthe, that long reverb on her voice and the carefully woven loops that make up the body of her music are still very evident, but this time around, due to relocating to Iceland for this recording, and collaborating with like-minded musicians there, Nepenthe comes across as a significant progression for her.

In ancient Greek literature, and also in the stories of Edgar Allen Poe, nepenthe was a drug of forgetfulness used to wipe out grief and sorrow. The title suggested itself to Julianna, who experienced a death in her own family in the middle of making the record, but it also refers to the music consoling her during the isolation she was going through. She was on her own in unfamiliar Iceland and she needed to forget her previous musical adventures in Brooklyn in order to forge something new.

The biggest difference with Nepenthe, apart from the location, is that it marks the first time that Julianna has worked with a producer, in this case Alex Somers of Sigur Rós. Whilst her previous two albums had been recorded by herself, in isolation in her Brooklyn bedroom, this time she worked in a studio with Alex and a cast of musicians including a teenage choir and the Sigur Ros-affiliated string players Amiina.

It comes as no surprise that Nepenthe does remind the listener of Iceland's biggest band, but it is to Barwick's credit that this album sounds distinctively hers, and she has taken on their influence rather than being overwhelmed by them.

The steady swell of voices on the album opener 'Offing' underlines this, and creates an almost choral howlround. The collaborators aren't really evident until 'The Harbinger', the longest track on the album, with a melody drifting over glacial scraping effects and piano chords into a pretty, epic refrain.

This is a subtly experimental record. On 'Labyrinthine' the voices are almost in counter point to each other as the songs drifts without central focus, reaching in different ways, and on 'Crystal Lake' the looped voices are coupled with a manipulated, distant piano.

'Adventurer of the Family' is a quiet mix of strings and voices, 'Pyrrhic' brings a note of melancholy, and 'Waving to You' is a quiet goodbye. 'One Half' is the only track to feature conventional lyrics, which is almost startling as the rest of the album is lyric-less but still dominated by vocals.

'Look into your mind' is where the two worlds meet, again those loops are on the edge of feeding back, and they are overlaid with the sounds of that young choir and the strings of Amiina. The choir is also prominent on 'Forever', which seems to get more rootless, more groundless, as it develops and spirals off into the air. So much music gets described as ethereal, but there is no better adjective for this.

After a while you get lost in Nepenthe and forget that this is mostly voices, it manages to transcend its constituent parts and make a beautiful noise from start to finish.