Bjork Album Preview: Beautiful, Baffling and Bothersome Medúlla

New album consists almost entirely of vocals.

"With a palm full of stars/ I throw them like dice on the table/ Until the desired constellation appears," Björk sings on "Desired Constellation," from her forthcoming seventh album, Medúlla.

That might well describe her method behind Medúlla's madness. The album is an ambitious project — and not just because it's almost entirely a cappella. The songs are pretty unusual, as well. Some could be medieval hymns; others could be modern pop songs; others are almost indescribable. But throughout, Medúlla is a strange journey that can leave you feeling elated or unsettled, without quite understanding why.

Thanks to a team of beatboxing and throat-singing collaborators, Björk's not alone in this journey. Former Roots member Rahzel helps add menace in her warning to her younger brother, "Where Is the Line," and returns to keep "Triumph of a Heart" grooving. But the cast of characters (which also includes ex-Faith No More singer Mike Patton, Robert Wyatt, Japanese beatboxer Dokaka, Inuit throat singer Tanya Tagaq Gillis and a 20-piece choir) flit in and out as Björk sings over them, creating vocal symphonies and cacophonies alike.

As with 2001's Vespertine, Medúlla is largely an introverted record, but that doesn't mean it's without drama or even a sense of dance. Björk has said she chose the title because it means getting to the essence of something in a medical sense, but musically, she's getting to the essence of her voice — letting its textures and timbres blend and separate from the other voices, with hers sometimes buried (as on the duet "Submarine," with Wyatt) and then gushing forth to take the lead. Combined, the sounds are alternately angelic and demonic, joyful and mournful, otherworldly and, at times, downright irritating.

"Oceania," which she plans to sing at the opening ceremonies for the Olympics on Friday (and which the singer wrote specifically for the event), is one of those polarizing songs, with its Ethel Merman-like synchronized vocal sweeps that do suggest the aquatic, in a 1950s sort of way.

The Medúlla experiment works best when Björk has material worthy of her voice. "Who Is It (Carry My Joy on the Left, Carry My Pain on the Right)," despite its cumbersome title, is the most immediate and catchy number, with a pure sense of seize-the-day joy: If there is to be a single released from the album, this should be it.

Alternately, the timeless-sounding lament "Vökuró" ("Vigil" in Icelandic) is sweet and solemn, and though Björk sings it in her native tongue, its effect requires no understandable lyrics. The plaintive "Desired Constellation" is a little softer but more discernable, with its heart carried on Björk's questioning lyric "How am I going to make it right?" Björk is also at her best when she's not Björk, but when she's e.e. cummings. "Sonnets/Unrealities XI" borrows liberally from cummings' poem "it may not always be so" — and he gets a writing credit.

Medúlla isn't purely a cappella; piano chords do make an appearance on "Piano II," balancing some of that song's yelping and guttural noises. And the programming — if it is that — on "Mouth's Cradle" helps blur the line between whether it's vocals or chords you're hearing in between the pitch-shifting beat and chopped up vocals.

For Björk's experiment to have any lasting effect, the difference between the two should remain a mystery.