It’s easy to forget about múm. As Iceland’s third place musical export, they get a little lost in the shadow of Björk and Sigur Rós, their music as understated as the lower-case of their name and never screaming in a vie for our attention. For sixteen years the band have been quietly, quietly pushing their slow-builds of wispy vocals and glitchy beats, swelling strings and low-key piano, their albums closer to a dream state than a collection of songs.

Like a dream, recalling múm’s music is tricky. It hangs at the edges, at the fringes of language, difficult to grasp and harder still to describe – a gossamer of whispers and shadows, childlike and playful yet often jarringly intense. Sure, they’ve crept closer towards poppier structures in recent years, with 2007’s Go Go Smear The Poison Ivy leaning towards the whimsical and 2009’s Sing Along To Songs You Don’t Know opting for choruses more than experiment, but they’re still pretty damn far from mainstream: not even last year’s collaboration with Kylie, the jittery, hyperactive ‘Whistle’ (here included as a bonus track) could render them conventional.

Smilewound, the band’s sixth studio release, signals a circle of sorts with the return of original vocalist Gyða Valtýsdóttir, last heard on múm’s 2000 debut album. Yesterday Was Dramatic Today Is OK was a strikingly contradictory listen, veering from lullaby to nightmare often within the same song, with Gyða’s vocals (and those of her sister Kristín Anna) the only anchor against the dissonance: by comparison this is a far more upbeat collection, with little of the insularity and claustrophobia that characterised that collection. The disparity was illustrated during their Latitude performance in July, a set primarily comprised of new material, joyous and warming and effortlessly elating, and one song from that early era, ‘The Ballad Of The Broken Birdie Records’, which Gyða accompanied with a repeated mime of a bird breaking its neck for five minutes.

But hey, happy’s good, and what with Sigur Rós turning to the shadows for Kveikur and Björk sciencing up for Biophilia, there’s certainly room in Iceland’s export manifest for something a little lighter. And Smilewound is frequently very lovely, even if its title does reference a mafia punishment. Opener ‘Toothwheels’ is staggeringly, disarmingly pretty, a vibrant assembly of cascading strings and tickled ivory, whilst mid-album highpoint ‘The Colorful Stabwound’ tempers its melancholic lyrics with compulsive melodies and fevered percussion. ‘Underwater Snow’ moves from piano balladry to a cacophony of sounds, Valtýsdóttir’s breathy vocal cushioned by echoed drums and bubbling synths and erratic clicks, and ‘When Girls Collide’ melds its harmonies with chiptune, a folksong stumbling drunkenly out of a Tokyo arcade.

There’s something of a kitchen-sink approach to songwriting here, and tracks such as ‘Candlestick’ get a little smothered in the clutter. The attempts to pare things back a bit have mixed results as well: instrumental ‘Eternity Is The Wait Between Breaths’ clearly aims at the atmosphere of múm past but never quite gets there, striving for experimental at the cost of being memorable.

But there’s enough invention, enough kinetic restlessness that it doesn’t matter: Smilewound’s gleeful, weird-pop eclecticism builds up the goodwill to cover any lull. And of course there’s always Kylie, buried at the back of the album as though her appearance barely matters – which, in truth, it doesn’t, as by the time the preceding forty-five minutes have rolled around we’ll accept anything múm do as normal. We just might not quite remember it when we wake up.