In his native Norway, HP Gundersen’s something of an uber-producer, a hit-maker extraordinaire in the gray area between mainstream rock and hipster cool. Against this background, this debut outing by the Bergen-based producer’s collaboration with singer Heidi Goodbye comes across as much-needed respite from the commercial pressures of the day job. These defiantly strange, profoundly uncommercial outpourings can only be the sound of talented musicians with a wide range of references seeking to please only themselves, the outcome’s joyously sprawling, unpredictable freedom making the album recommended listening to anyone with ears open to new ideas where it’d have so easily unravelled into a self-indulgent mess.

Imagine already relatively far-out psych/odd/strange/acid folk merchants stumbling onto a psychotropic plant so fearsomely potent in its disorientating powers even the most foolhardy of shamans would steer well clear of it, using it as a key ingredient for a stew and munching the lot before embarking on a truly gigantic jam starring several drone-favouring guitars using various modal tunings, percussion, sax, harmonica, vocals and the kitchen sink, and you’re not far off the all-conquering oddness of the 30-odd (!) minute centrepiece ‘The Ballad of Billy and Lilly’. Using mind-altering substances as a metaphor for describing music is a knackered old trick, but there really isn’t any other way to make sense of this restlessly shifting – spots of tender fingerpicking, bits of sweetly cooed folk balladry, a pinch of hard-boiled slide guitar and even the odd outbreak of woods-dwelling stomp-funk – epic, the wildly disparate sections of which somehow cohere into a seamless whole that is, although initially challenging, certainly several shades more arresting than yet another bunch of bleary-eyed modern minstrels dreaming up their very own Wicker Man soundtrack.

To be fair, it’s hardly faultless. Encountered in the wrong mood, ‘The Ballad…’ can come across as a bunch of half-baked snippets forced to co-exist by judicious editing as opposed to a visionary outbreak of epicness. Although they add a touch of humour into the kind of experimental fare that’s usually firmly in favour of a frown, the forced, cheesy rhymes (Billy/Lilly/silly/really…) can also grate. On balance, though, especially with the addition of an appealingly hazy cover of Norwegian cult band Oriental Sunshine’s world-hugging Mother Nature and the surprisingly robust bossa strut of Melodi Grand Prix 73 that closes the proceedings, Spiritual Non-Believers is an impressive opening from a beguiling project.