Jón Þór Birgisson likes to play. Under the mononym of Jónsi, the Icelandic musician is mischievous, enigmatic, almost imp-like. This imbues his projects with a sense of childlike wonder and lightness, whether augmenting the cinematic orchestral sweep of his day job as lead singer of Sigur Rós, the amorphous ambient sounds of his work with ex-partner Alex Somers or the more energetic, pop-oriented songwriting of his solo debut, 2010’s Go. Following up with his second solo record 10 years on, Jónsi finds an unlikely kindred spirit in producer A.G. Cook. Best known as the mastermind of experimental pop collective PC Music and for his work with Charli XCX, Cook’s tactile, slick, mad-scientist approach to making music folds around Jónsi’s irrepressible earnestness on Shiver. This makes for an intriguing collection of songs — exhilarating at their best, though just as often simply awkward and curious.

In many ways, Jónsi and Cook’s approaches are diametrically opposed. Jónsi’s appeal both independently and in Sigur Rós comes from coaxing wet-eyed sentimentalism out of broad, lush sonic landscapes, but it’s shot through with a lack of pretence, a wry glint in the eye. Conversely, Cook’s signature sound is busy, bright and energetic;  a cavalcade of glistening synths and chopped vocals. But within the mania is an innate seriousness about the process. Across Shiver, the two modes interlink and contrast in surprising ways as Jónsi provides the album’s heart and Cook its brain.

Opening track”‘Exhale” sets things up with a sparse piano chord introduction and a lethargic vocal. It’s gentle, tentative and very much in step with what regular listeners might expect, unfolding as it does into a lush and generous chorus in which Jónsi’s vocal soars to proclaim “This is the way it is / It isn’t your fault /Just let it go.” Cook’s signature tendencies creep in subtly as the track unspools. Ascendant strings are underlaid with chopped-up vocal samples and a cranking industrial beat that echoes on the edges. It is a gentle augmentation that makes itself increasingly known on subsequent cuts — title track “Shiver” has a wailing, operatic vocal line that is driven along by a throbbing synthesised bass undercurrent. The push and pull between Jónsi’s soft naturalism and Cook’s abrasive synthesis typifies several entries on the album, as with the clatter-bang dissonance of “Wildeye” which threatens to overpower the deep yearning of Jónsi’s voice.

Some of the best moments come in those lighter augmentations, as with the layered a cappella harmonies of “Sumarið sem aldrei kom,” which enjoy a light electronic processing to sound like a space-age hymn. As the piece builds, a thrumming synth organ and cavernous drums give Jónsi the sort of big stadium moment he thrives on, as calibrated through the PC Music lens of technology.”‘Kórall” is just as appealing, built on a pulsating lullaby-like chime and compressed vocal lines before exploding into a sugary, massive and unashamedly pop climax. On “Swill,” a marriage of huge indie-anthem melodies with hulking, cranking instrumentals akin to the signature doom-pop sound of frequent Cook collaborator SOPHIE is another impressive and successful coming-together for the two creators.

One thing Cook most demonstrably brings to the table, too, is his collaborative spirit — apparent in the enthusiastic deployment of guest appearances throughout Shiver. As with much of Cook’s work as an overactive overseer, there’s an appealingly frantic if consistent streak to this particular element of the album. The melding of Jónsi’s vocal with the ethereal tones of Elizabeth Fraser (of Scottish shoegazers Cocteau Twins) on “Cannibal” is an ideal match, famous as both singers are for effusing nonsense lyrics in invented languages with pathos and beauty. The track itself is a moody number with gritty guitar arpeggios interspersed with glittering electronic sounds. Its dual voices float above the mix, conveying grim, visceral lyrical imagery in uncharacteristic English. More puzzling is “Salt Licorice,” featuring Swedish dance-pop superstar Robyn. Rather than playing to the emotive strengths of Jónsi and his guest, this is a propulsive, clubby track that stomps along on a siren-like beat. It’s harsh and perplexing, with the two vocalists screaming about “my Scandinavian pain” over the cavalcade. There’s fun to be had, as there usually is with these particular artists, but not as you’d expect.

Perhaps understanding that their collaboration only has so much mileage, Jónsi and Cook tilt harder into the former’s signature palette as Shiver reaches its close. “Grenade” is a mournful track — Jónsi laments “it’s too late” over low pianos and a sweeping, mostly organic instrumental, while the final track “Beautiful Boy” is a sentimental, tender closing note that brings the focus almost solely onto the singer’s vocal. Where the album’s midpoint is a delirious, sometimes exhilarating, sometimes misinformed explosion of experiments, these final songs are a less daring but more assured realisation of the Jónsi template and how it can be tweaked and pushed. Dissolving into a tranquil, formless ambience in its final moments, “Beautiful Boy” puts heart before brain. While Cook clearly has his hands on deck operating the machinery, the closing tracks make clear that it’s still Jónsi steering the ship, as impish and wholeheartedly earnest as ever.

Rhys Handley (@RhysHandley2113) is a journalist and film writer from Yorkshire in England. Now based in London, he is the biggest Talking Heads fan who still hasn’t seen Stop Making Sense.