The majority of the tour was European with the exception of concerts in the United States, Australia, Canada and Japan.

[6][7] Despite being on a break, the band began recording for the album in March 2009 with Alex Somers, with some of the songs dating from 2007.

But then something happened and form started to emerge, and now I can honestly say that it's the only Sigur Rós record I have listened to for pleasure in my own house after we've finished it.

"[14] The album opening track "Ég anda" has been described to have "reverb-heavy guitars chiming quietly before Jónsi's distinctive falsetto floats in over what sounds like an army of music boxes".

[4] On 26 March 2012, the band announced the details of their sixth studio album, along with the premier of their new track "Ekki múkk".

[23][24] On the same day, Zane Lowe premiered another brand new track from the album, "Ég anda", on BBC Radio 1.

[28] On 21 August, the song "Varúð" was released as single in a special limited edition 10-inch vinyl to coincide with their 2012 summer tour.

The idea is to abandon the usual approval process from Sigur Rós, and allow film makers utmost creative freedom.

[31] Among the twelve filmmakers working without brief to a chosen song are Ramin Bahrani, Alma Har'el, John Cameron Mitchell and Ryan McGinley.

[35] AllMusic writer Tim Sendra said the album was "filled with giant washes of sound bathed in reverb, echoing keyboards, smears of strings, and massed backing vocals, the album ebbs and flows from giant crescendos to heartbreakingly intimate moments with Jonsi's otherworldly voice riding the waves like a mythical dolphin", ending the review saying, "On the surface, Valtari may seem like a step back for the band, but instead of just retreading the past, the album is one of their best; a refined display of their musical power with breathtaking dynamics and enough emotion to flood an ocean.

Club said that "the relative restraint on the single 'Ekki Múkk' and other more straightforward songs like 'Varúð' and 'Rembihnútur' is a welcome shift for the group, ditching the bigger-is-better grandiloquence and predictable arcs of Sigur Rós' recent work.

"[37] BBC Music writer Wyndham Wallace said that "much of the album sounds like it's made up of what would, in previous years, have only qualified as the introductions to songs.

Opening track "Ég anda" takes an age to get underway, reverb-heavy guitars chiming quietly before Jónsi's distinctive falsetto floats in over what sounds like an army of music boxes, and, though Rembihnútur lifts off towards its end in a familiar fashion, drums are largely limited to distorted electronic pulses and there are none of the earth-scorching effects that have previously characterised similar moments," and that "for those more patient, however, the album represents calm after a storm, and highlights how Sigur Rós remain as eager to challenge themselves as their audience.

"[15] Drowned in Sound stated that "this is not an album of easy melodies, of playful riffs and crowd-pleasing moments.

They later said that "Valtari seems rather brave: across a runtime of nearly an hour there's little effort to hold our attention, to vary the tone or venture anywhere, anywhere near mainstream appeal.

[39] Pitchfork was not so positive either, stating, "The problem isn't that Valtari aspires to beauty, even if it's a commonplace, celestial understanding of it.

"[41] Rolling Stone said that "Jónsi's exquisite vocals evoke prayers or lullabies, while pecked-out piano melodies play amid dulcimer tones, sonar burps, elf choirs.