After a fully-realised debut that threatened to serve as both their introduction to the world and their insurmountable, definitive statement, Alt-J suffered the dreaded Curse of the Mercury Music Prize, delivering the aggressively tedious and inexcusably bloated sophomore effort, This Is All Yours. Three years on from that, the trio return with an album that finds them following their creative muse down some head-scratching paths.

Let’s get one thing out of the way early and save everyone some time. Your enjoyment of Alt-J’s music from their 2012 debut right through to their new album, Relaxer, lives or dies depending on your tolerance for the particular brand of college dorm pretentiousness that inspires quality-control-deficient acts to deliver choice phrases or entire verses in foreign languages, make obtuse literary and cinema references, or (heaven forbid) spell out words or sing in some kind of code. If none of those things put you off, by all means, read on and take a listen at your earliest convenience. If your eyes have already rolled back harder than Anderson Cooper’s during a CNN interview with Kellyanne Conway, then cut your losses. Alt-J are not the band for you.

The unavoidable fact is Alt-J are divisive. There can’t be too many bands out there who have won the Mercury Prize whilst having an average Pitchfork review score of 4.4; who can headline major festivals with a singer whose voice has been unfavourably compared to both Macy Gray and a goose. They’ve been dubbed the ‘New Radiohead’ and, in other circles, been roundly mocked for how short they fall in that comparison. They inspire rabid devotion from their fans and sneering derision from their detractors. They’ve even managed to provoke both responses from yours truly. An Awesome Wave was probably my most listened to album of 2012; it was endlessly replayable, well sequenced, filled with hooks, and, thanks to its strange juxtaposition of a cappella vocals with folk guitar stylings and dark trip-hop-indebted beats, it sounded like something new (by alternative indie standards). But where An Awesome Wave left an impression of charming effortlessness, its follow-up This Is All Yours felt over-laboured, and, when it wasn’t painfully dull, it bordered on obnoxious.

Relaxer highlights the best and the absolute worst of Alt-J. That’s what makes it such a frustrating, and yet fascinating, listen. Opening with ‘3WW’, Alt-J are pitching straight for the exotic with Tinariwen-esque finger-tapped guitars over a lumbering beat that brings to mind an ambling camel ride over desert dunes. This continues for a while, with a general sense of being pro-tools looped into lifelessness. At the 1:10 mark, what sounds like a snore rises up in the mix; an unfortunate but befitting percussive accident. Gus Unger-Hamilton’s are the first vocals we hear: an incongruous, pastoral-folky, keening cadence to his voice. He talks of a “wayward lad” leaving to go camping with the sky as his awning. The "Green of England" mystical tendencies that hamstrung This Is All Yours have unfortunately survived to blight album #3. After a verse by Joe Newsome, ‘3WW’ suddenly bursts into life with possibly the best chorus Alt-J have ever written, wherein each line has a distinct but emotionally resonant musical backing. The twinkling pianos that play under the plea of, “I just want to love you in my own language” constitute the album’s most beautiful moment.

The rest of the song weaves the tale of said “wayward lad” having his first sexual encounter with two “thirsty girls from Hornsea,” who leave him in the morning with a note mocking his naïveté and the residual smell of sex that’s “good like burning wood.” What this song proves, like ‘Fitzpleasure’ on An Awesome Wave, and ‘Every Other Freckle’ on This Is All Yours also did, is that Joe Newsome really must stop writing lyrics about sex. He is, in essence, a man who desperately needs to be relieved of the delusion of his own sexiness. Later, Ellie Roswell of Wolf Alice pops up to do her best lascivious Lana Del Rey impression and, despite singing about the deeply unerotic topic of land erosion, she manages to lift the song and help make it into the high point of the album.

‘In Cold Blood’ follows and feels like a spiritual sequel to ‘Left Hand Free’, in that it’s quite conventionally rocky, supremely silly, and kind of fun, in a “should I really be enjoying this” kind of way. It also features a brass section, as is compulsory for any self-respecting 21st Century indie rock song. The guys have talked about how the song features a keyboard they bought off eBay for little over £1. The problem is, it fucking sounds like it. Just a terrible, terrible keyboard tone. Combine that with singing “01110011” and “Pool, summer, summer, pool, pool summer” bullshit, and you’re left with a song that appears to be trying to shoot itself in the foot while you’re listening to it.

The perplexing choices continue with track 3, a cover of ‘House of the Rising Sun'. Not the classic version by The Animals, mind; theirs is an interpretation of the traditional folk song, replete with additional lyrics and an “orchestra” of 20 classical guitarists. It’s atmospheric and certainly swells with the requisite gravitas; the sound of 20 synchronised guitar string squeaks makes for an interesting percussive element. And yet, something about the whole thing rings false. Why cover that song? How does it fit in thematically with the remainder of an already disjointed album? It just feels a bit forced, as if a talking point for a press release is being generated, rather than anything with bona fide artistic purpose. The clickbait article title essentially writes itself: “This British rock band covered 'House of the Rising Sun' with 20 classical guitars playing simultaneously, and you won’t believe what happened next!”

What happens next is that Relaxer - and Alt-J’s entire oeuvre - reaches its absolute nadir with ‘Hit Me Like That Snare’, a song that, according to accompanying press materials, purports to sound like The Stooges produced by James Murphy. It’s a comparison that casts heinous aspersions upon both artists. ‘Hit Me Like That Snare’ is, simply put, a mangled car wreck of a song. You want cowbell? Check. More cowbell? Check. B-movie horror synths? Check. Hideously obnoxious nasally vocals? Check. Bleeped out references to fisting? Check. Singing in Japanese? Oh, for fuck’s sake. And that’s all before the coup de grace of the final refrain of “FUCK YOU! I’LL DO! WHATEVER I WANT TO DO!”, which somehow manages to be more petulant than Rage Against The Machine’s “FUCK YOU! I WON’T DO WHAT YOU TELL ME!” It’s an irredeemably bad song; obnoxious and grating in all the worst ways. I don’t know if the Alt-J boys have discovered cocaine now that they’re bona fide “rock stars,” but this song suggests they may have done. Honestly, I’d rather listen to that Alt-J parody song about putting things in your bum than endure ‘Hit Me Like That Snare’ again.

Thankfully, the second half of this mercifully short album finds Alt-J redeeming themselves to some extent. ‘Deadcrush’ is actually a decent listen. It’s got a brooding, menacing bassline, a beat that slaps hard, and it remains more or less cohesive in tone throughout. Not even Joe Newsome’s best/worst Scissor Sisters impression can tarnish one’s enjoyment of this song. It's an exciting direction for Alt-J and makes good on their promise of being a post-guitar band for the new pop generation. Shame then that 'Adeline’ feels like a bit of a throwback to the drawn out moodier tracks off their debut. Despite that, and the hugely irritating “yah yah yah yah” backing vocals that signal the beginning of the song’s build towards its admittedly affecting crescendo (which will be soundtracking a YouTube supercut of epic scenes from Game of Thrones any day now), there's no doubt that 'Adeline’ is likely to be a fan favourite and first choice for set closer at the band’s summer festival slots.

The two-hander that plays out the album highlights the fascinating dichotomy and tragic flaw at the heart of Alt-J. They are a band capable of subtlety, as on the delicately finger-picked (if somewhat unmemorable) folk of 'Last Year’, whose lyrical conceit details a calendar year of a deteriorating relationship. However, they’re also capable of near hysterical, everything-AND-the-fucking-kitchen-sink, hyper-bombast as on the plainly baffling closer 'Pleader’, which combines passages of horror film atmospherics and farting basslines, with what can only be described as extended excursions into, erm, devotional church rock - immense pipe organs and a boys choir included. “How green, how green was my valley?” Newsome sings, reminding us earnestly that, yeah, he reads books. It's all rather ludicrous in its unearned grandiosity.

And that tragic flaw that Relaxer reveals? Well, it's the stuff of nightmares for a band as self-serious as Alt-J; it's that when they aim for subtlety, they end up being Mumford-levels of boring, and when they attempt to push the bracket and heighten the drama, well, more often than not, they just sound a bit silly. At least we'll always have An Awesome Wave.