The Icelandic singer Björk has a gift for making albums that sound both unique and completely familiar. That’s what makes her new album, “Volta” (Atlantic), such a comfort and a disappointment. It is lustrously expressive, rhythmically adventurous, hauntingly beautiful — and exactly what fans expect from the New York-based artist, despite its eclectic mix of collaborators.

“Volta” is, in many ways, the ephemeral endgame of the polyglot experimentation that Björk undertook on 2001’s luminous “Vespertine.” On that album, she stripped her already minimal approach to its basest essences. The music on that album, made in collaboration with the ambient techno duo Matmos and the avant-harpist Zeena Parkins, felt as insubstantial yet opaque as fog, something you could pass through without effort yet it still obscures your way.

That spectral approach spotlighted what makes Björk’s albums so uniquely intoxicating: As her music provides the rhythm and texture, her otherworldly, acrobatic voice becomes the only melodic element. From the Nellee Hooper-produced “Big Time Sensuality” (off 1993’s “Debut”), which announced Björk’s ingenious use of contemporary dance music in pop songwriting, through her longtime fan favorite “Hyperballad” (from 1995’s “Post”) and on through the butterfly-wing fragile love odes “All Is Full of Love” (from 1997’s “Homogenic”), Björk is the rare pop artist who treats music as the merest of background settings for her intricate, emotive vocal reservoir. She’s the intrepid actress on her songs’ nearly empty stage.

With that voice Björk has always been more than capable of filling her songs with bottomless layers of thoughts, emotions, fears, anxieties, and hopes. “Homogenic” testified that Björk was more than the Icelandic pixie of her popular image, capable of anger, tenacity, and defiance on a song such as “5 Years,” where she almost growls “I dare you to take me on” and “You can’t handle love,” and the devastating resignation of “Immature,” on which she painfully howls, “How could I be so immature / To think he could replace the missing elements in me.” She’s had this limitless range for her entire adult life — just revisit her 1980s postpunk band, the Sugarcubes, or Kukl, the Pylon-meets-Tones on Tail avant-goth outfit with whom she sang before that.

Björk’s recognition of her voice’s — and that of the human voice in general — infinite possibilities peaked with 2004’s “Medulla,” an album knitted together entirely from voices and vocal samples. Featuring the voices of British, Icelandic, and Inuit choirs, plus Mike Patton, Robert Wyatt, and the Roots beat-boxer Rahzel, “Medulla” felt and sounded like the culmination of Björk’s creative enterprise. On it, she erected emotional swells out of linguistics, transforming sound systems — glottal stops, bilabial fricatives, and Icelandic’s pre-aspirated consonants — into a musical palette as elastic and expressive as paint.

Now comes “Volta,” which will be released tomorrow and sounds like more of the same far too often. Made with the help, once again, of a stellar cast of collaborators — including the Congolese rhythm masters Konono No. 1, free-improvising percussionist Chris Corsano, hip-hop pop production whiz Timbaland, Lighting Bolt drummer Brian Chippendale, Malian kora player Toumani Diabaté, and a 10-piece, all-female Icelandic brass section — “Volta” is unmistakably a Björk album. The percolating trance track pulsating through “Wanderlust” provides a throbbing foil to Björk’s soaring vocal and the funereal horn sections. The song peeks into Björk’s creative thrust: “Lust for comfort suffocates the soul / Relentless restlessness liberates me” she sings, which is practically a blueprint for her musical career.

The problem with being so incontrovertibly singular, though, is the danger of perpetual sameness. Whatever Björk cooks up comes out sounding like Björk, no matter who else is in the kitchen. The horn section establishes the dirge-like pace of “The Dull Flame of Desire,” a duet with Antony Hegarty of Antony and the Johnsons. Mr. Hegarty, even though he always sounds as if he’s auditioning for the Tindersticks, has a peculiar voice himself, but the viscus pace and slowburn longing of the song is pure Björk, and a testament to her slow, soul-kiss approach to love songs, perfected on “All Is Full of Love,” from “Homogenic.” A subtly atmospheric electronic landscape and those horns again underscore “Pneumonia,” a mournful swatch of resilience seeking that slowly becomes a baroque tapestry — exactly like what she quilted on “Pagan Poetry,” from “Vespertine.”

Of course, the real fireworks on “Volta” are supposed to be thrown from the Björk-Timbaland pairing on three songs, the very news of which sent online music critics posting ecstatic, anticipatory blog posts. Too bad “Innocence,” “Hope,” and the lead single, “Earth Intruders,” not only fail to make the brain melt, but can’t even touch Timbaland’s work on Justin Timberlake’s “Future-Sex/LoveSounds.” The fleshy, belching beats of “Innocence” in particular sound like Timbaland throwaways and nowhere near the usual forward-edge of dance pulses that Björk favors.

Of course, below-par Björk is still head and shoulders above her peers. “I See Who You Are,” which features the Chinese pipa player Min Xiao-Fen, is a floating dream of a love song, with the pipa’s mandolin sound painting a scroll of moods behind the singer’s longing lines. Taken alone, the music could be a throwaway soundtrack score in some forgotten movie; with Björk singing above it, it becomes indelible.

And that’s what most distressing about “Volta”: It’s obvious that Björk hasn’t lost her innovative panache, it’s just that she clearly needs to be taken out of her songwriting comfort zone, even just slightly. And why not? At 41, Björk is two decades into her career, taking more risks than artists of either gender 20 years her junior, and widely adored. Each successive album since 1993’s “Debut” has broadened her audience, as have her alwaysinnovative music videos, which can still win over MTV surfers who might not have picked up the albums. But maybe they don’t need videos anymore; “Volta” is, above all, a very accessible outing. And if it inches Björk toward the mainstream success enjoyed by such MTV staples as Mary J. Blige or the Dixie Chicks, she’s more than earned it.