There's a moment near the beginning of track two of Love Letters which epitomises the unpredictable novelty of Joseph Mount. The sudden recurring 'shoop-doop-doop-ah' of 'I'm Aquarius' distils those strands Metronomy weave together to create a sound charmingly out of step with both the pop and electronic spheres. It was for this concoction of '80s synth and pop sensibilities that 2011's Mercury-nominated The English Riviera deservedly received critical attention. Here, on the group's fourth album, it's classic pop that augments the familiar new wave/Krautrock aesthetic. Though less accessible than its predecessor, Love Letters' ten tracks are a sequel to that toned-down record, but while pleasantly soulful, its forty mostly mellow minutes lean too heavily on ponderous restraint.

'I'm Aquarius' is an early highlight; the sentiment is heavy-hearted, but the groove is smooth. Such retro tributes are scattered throughout: Mount's unabashed fondness for vintage pop shines through the classic psychedelia of 'Month of Sundays'. That said, Metronomy's roots lie in quirky instrumental electropop, so the appearance of hooks akin to Mount's early career output come as no surprise. The blippy 'Reservoir' is delicate, earnest synthpop, while 'Boy Racers''s funky instrumental jam recalls Gershon Kingsley's 'Popcorn'. Trite muzak 'Boy Racers' may be, but its Italo-disco handclaps and hi-hats are irresistable.

Lyrically, Mount tells of melancholy and damaged relationships. His mild vocals accompany the songs rather than dictate them, which saps an otherwise dynamic 'Call Me' of its vitality. More than once, doses of underwhelming mid-tempo electronica derail Love Letters. Recorded at London's Toe Rag studios, the album is wilfully analogue. 'Monstrous', for example, requires a high Casio-threshold. Love Letters' eponymous single goes some way to redeeming its missteps, though. Combining Abba-esque keyboards, ELO and a hint of Motown, the maddeningly infectious refrain stands notably apart.

When Love Letters works, its idiosyncratic electropop occupies a snug mellifluous milieu between pop and rock. Love Letters could be filed in proximity to Hot Chip, but with deference to the Gallic electronic inspiration of Air or Jean Michel Jarre. It's tempting to crave more toe-tapping from a band that sounds like it's holding back. True, Metronomy were never the party band some will them to be, but the demo-like underproduction on top of Mount's focus on song-writing renders a few tracks overly thin. Love Letters is enough to maintain the band's upward trajectory, but there's too much here that fails to leave a mark.

Review by Killian Barry