The British electro-pop duo Goldfrapp radically reinvents itself for “Seventh Tree,” its fourth studio album, out today. The makeover isn’t just creatively and commercially surprising — both 2003’s “Black Cherry” and 2005’s “Supernature” were glam, libidinous dance-pop affairs that charted in both Britain and America, with the latter earning a 2007 Grammy nod for Best Electronic-Dance Album — but also remarkably successful. “Seventh Tree” is a woozy wash of psychedelic folk music seamlessly breeding with ambient electronic dreamscapes. Those two disparate genres combine to make unexpectedly engaging pop songs, and the album cunningly updates a genre that another British act pioneered in the late 1960s. Think Fairport Convention.

“Seventh Tree” announces Goldfrapp’s new direction from the very first notes. Where previous albums opened with synth throbs and dance-floor bass lines, “Seventh Tree” begins quietly with “Clowns,” a gorgeous tapestry of acoustic guitar laced with an electronic ebb and flow. Over this hushed production, Allison Goldfrapp sings in a deft sotto voce, never once sounding like the robotic Weimar Republic sex machine that has typically complemented the duo’s disco-fied decadence. “Clowns” has more in common with Joanna Newsom and the modest, ethereal folk on the Finnish Fonal Records imprint than anything from Goldfrapp’s first three albums. Will Gregory and Ms. Goldfrapp sound as confident and comfortable in this dreamy mode as they ever have. That assurance runs through the next nine tracks, from the abstract lullaby “Little Bird” to the pastoral closer “Monster Love.” At no point does “Seventh Tree” rattle the speakers with thundering camp, as Goldfrapp did on “Ride a White Horse” (from “Supenature”), a track that cheekily hitched a ride on Bianca Jagger’s infamous entrance to Studio 54 atop a white horse on her 30th birthday in 1980. Not only are Goldfrapp’s bombastic, glittery beats and blue eye-shadow sparkle gone, but so are the meta-awareness in-jokes that informed “Ride a White Horse” and Goldfrapp’s previous visual and aural output.

That’s not to say that Goldfrapp doesn’t mine the past, but the duo is less interested in congratulating itself for its every allusion. The climbing keyboard lines and Ms. Goldfrapp’s soaring harmonies in “Happiness” recall the sunset highs of late 1960s psychedelic pop, but the duo lets the song make that connection on its own terms rather than hard-wiring it with a “Pet Sounds” sample or a “Strawberry Fields Forever” quotation. And the slinky bass, keyboard funk, and agitated strings that make “Cologne Cerrone Houdini” such an alluring strut feel inspired by Serge Gainsbourg’s 1971 album “Histoire de Melody Nelson,” a bellwether mark of moody, conceptual seediness that has inspired everybody from Air to Portishead. Goldfrapp’s deft twist undercuts the steamy bass and strings luridness with Ms. Goldfrapp’s breathy rejection: “I’m not your kind, I’m not your girl / See I’m in your car but not your life.”

Similar frictions populate Ms. Goldfrapp’s lyrics on “Seventh Tree.” The golden melodies pushing “Happiness” into the ether cloak a tale about getting lost in a cult: “Join our group and you will find / harmony and peace of mind,” Ms. Goldfrapp sings like a siren, an invitation whose motivation is cruelly spelled out in the chorus: “Time stops too when you’ve lost love / Happiness, how do you get to be happiness” — a rhetorical question the song never answers despite the euphoric drums and organs that enter at the two-and-a-half-minute mark. As a whole, “Seventh Tree” is a plush, bucolic album about fairly distraught matters. The song “A&E” features one of Ms. Goldfrapp’s most stirring vocal performances, singing from the point of view of a woman who only wanted to be taken out while high on pills because she was “feeling lonely, feeling blue” — and who regains clarity by wondering how she ended up in the emergency room. Propelled by a chiming guitar line and a gently rustling percussive thrust, “A&E” — “accident and emergency,” what the ER is called in Britain — recalls another upbeat song about boozy oblivion: Fairport Convention’s “Genesis Hall,” from 1969’s “Unhalfbricking.”

That connection spotlights the fact that although many contemporary folk acts such as Ms. Newsom, Devendra Banhart, and Animal Collective have resurrected the acoustic singer-songwriters of the American and British folk eras — from Judee Sill, Karen Dalton, and Linda Perhacs to Vashti Bunyan and Nick Drake — the landmark band albums of folk rock have been sidelined as less influential. Until now: “Seventh Tree” is an update of Fairport Convention’s electric folk rock, only this time around the electricity in question isn’t Richard Thompson’s guitar but Mr. Gregory’s and Ms. Goldfrapp’s keen electronics.

“Seventh Tree” might not be the same sort of transitional step for Goldfrapp as “Unhalfbricking” was for Fairport — if only because Goldfrapp already sounds fully realized in this new mode — but the album remains a bold, enthusiastic reminder that any band willing to push itself out of its comfort zone can suddenly hit upon even richer and more rewarding music.