Sound check: The feel bad hit of the summer

And yet over the summer, the relentlessly downbeat Swedish act have become one of the most talked- about on the festival circuit, their austere performances — incorporating Andreas Nilsson's incredible video projections — sending new fans out to seek their shimmering, claustrophobic debut album. The songs may not inspire much jumping around but will make a delightful change from being asked if you're having a good time.

Fever Ray, though expanded to a full band for this tour, is essentially the solo project of Karin Dreijer Andersson, 34, who, with her brother Olof, forms the secretive Swedish dance act, The Knife. That band's highly original 2006 album, Silent Shout — all fuzzy synthesisers, bass swoops and Andersson's eerie, strangled-child vocals — had a compelling touch of melancholy but with Fever Ray, Andersson strips away the disco, fully exposing her dark heart. Driving down an empty motorway at 3am would be the ideal listening situation.

Like many of the great albums, it has a particular genesis. It was recorded at home, after the Silent Shout tours had ended, during which time Andersson became pregnant. Since the admirable Swedish government provide 14 months of maternity pay, she could share parenting duties with her husband and find time to make her own music. A paean to the joys of motherhood this is not, however.

Andersson had suffered from insomnia since the birth of her first daughter, six years ago. "My first child has never been sleeping well," she tells me, her speaking voice almost unbearably vulnerable. "Everything becomes dark when you don't sleep."

In the twilight hours, she stalked their home on the outskirts of Stockholm and attempted to channel the subconscious thoughts that arose. "The whole experience of becoming a parent is quite a shock. When you have kids, you ask a lot of questions. You have been able to create life, and then you start to think about death a lot more and you realise the line between is so thin and fragile. You start to think about the opposite of life."

In a semi-waking state, she retreated to her small home studio where, with software and distortion effects, she created a series of ambient pulses, more moods than melodies, deathly slow. It comes across as an electronic update of the harmonium that underpins Nico's Marble Index and Desertshore (often cited as the most depressing albums ever made), with shades of Portishead and Björk at her most ambient, plunging the listener into an inky soup.

On top of these minimal soundscapes, Andersson layered her childlike voice, treated with effects that make it cracked and hoarse. She wrote the lyrics last of all, she says, to seep between the soundscapes. The fractured phrases speak of domestic psychosis: "I'm very good with plants/When my friends are away/they let me keep the soil moist," she is compelled to relate on When I Grow Up; "I live between concrete walls/ In my arms she was so warm" on Concrete Walls.

The whole is singular in its effect, with the minimal, Nordic clarity of an Ingmar Bergman film. Not many acts would cite brutal album Anonymous by the Native American metal band Tomahawk and Phil Collins's In the Air Tonight as their prime influences — "His voice effects are amazing," she enthuses without irony, disputing the idea that it is all gloom.

"I don't think of my album as so dark — there's a lot of hope in it, too. Music is a good format to go into ideas that you are unable to explore in everyday life." Like? "Death, horror and fear. You can go into certain feelings. When you discover them through music and they become not so frightening."

Indeed, when you emerge after 45 intense minutes of Fever Ray, the effect is cathartic, uplifting even. It will feature highly on best of 2009 lists when the year is out.

Even the children who inspired it like it. "But my six-year-old has her own taste in music now — she likes the Eurovision Song Contest," Andersson says. "And Twisted Sister, the heavy metal band — she loves Twisted Sister."

Fever Ray is out on Rabid/V2 Records.
David Smyth is away