Björk Gudmundsdóttir is sitting upstairs in a quiet restaurant in Reykjavík, just around the corner from the city's central Austurvöllur square and the Hótel Borg, where in the '80s she and her mates whooped it up as progenitors of Iceland's fledgling punk scene. These days, the now-stately Borg harbors few radicals, and the square, lined with tourist-friendly cafés, has gone mainstream. A massive banner ad for the Icelandic version of ''American Idol'' (Idol-Stjörnuleit) hangs over the park, with Bubbi, the chilly little nation's answer to Simon Cowell, scowling smugly at passersby. Surprisingly -- despite a hectic recent schedule that has included tending to her second child (Isadora, 2, whose father is the visual artist Matthew Barney), preparing an eye-popping number for the Aug. 13 opening ceremonies of the Olympics, and finishing up her fifth studio album -- Björk has actually watched Iceland's ''Idol.'' ''I don't know how they do it,'' she says, marveling at the contestants' ability to learn songs quickly. ''If I didn't like a song, I couldn't even open my mouth. But, obviously, [the show] is about being a performer and being able to thrive under ridiculous pressure. I'd be an awful American Idol. I'd totally blow it.''
That's not the only reason Björk wouldn't cut it on ''Idol.'' The 39-year-old Icelandic singer is one of the pop world's biggest risk takers, having released a string of wildly innovative albums over the past 11 years that have left music fans alternately awed and baffled. Her latest is no exception. Medúlla, due out on Aug. 31, has close to no instruments. A glacially paced, classically influenced set of deeply complex compositions, it is cast almost entirely from human voices: Björk's cathedral-rattling roar, the Icelandic Choir's gossamer highs, craggy art-rock legend Robert Wyatt's grim exhortations, and miscellaneous spastic whoops and mechanical-sounding riffs from a host of global larynxes. In a career marked by innovation and eccentricity, this may be Björk's most challenging offering yet.
She, of course, doesn't quite see it that way. ''I don't feel this record is that eccentric,'' she says. ''But then again, I'm probably the last one to know. I think of it as more of a 'going out' record.'' Excuse us: as in a party disc? ''[2001's] Vespertine was meant to be a really introverted album that people listen to alone in their house,'' she explains. ''It's introspective. It's not a club record, for sure. But this, I think, is pretty outgoing.''
Well, maybe if you grew up in Iceland. In a way, Medúlla is a natural product of Björk's upbringing, choral music being integral to Icelandic culture. ''My grandparents had a diamond wedding anniversary a few weeks ago,'' she says. ''They wanted all the family to go camping for the weekend. In the evening, everybody would sing together. I'm used to no instruments.'' To Björk, the melding of unaccompanied human voices can be a powerful communal experience, like when ''you go into a club and you're feeling really up, and then they turn off the sound system and people just sing together. For me, this is sort of a back-to-the-people record.''