The term "crooked" is sometimes applied to the oddly structured, Old World melodies that underlie American roots music. The Crooked Jades, therefore, is an aptly named vehicle for California-based bandleader Jeff Kazor’s mission: reconstructing the eclectic, idiosyncratic folk music that blossomed here before commercial interests began subdividing the sound of our immigrant melting pot into exploitable markets.

“We like to say we’re pre-radio,” Kazor says. “We’re into re-creating that cacophony.”

The Jades, who will perform Saturday at Radio Radio in Fountain Square, take an almost scholarly approach toward honoring and expanding upon the mountain string band format of the late 19th and early 20th centuries. Their domain is a nearly lost world that overlapped with the rise of recording and broadcasting but was perhaps too common to be thought worth preserving, beyond a few transcriptions and scratchy records.

The acoustic band’s fifth and latest album, World’s On Fire, is a mix of traditional and original ballads and instrumentals, with writing and arranging contributions from most of the quintet’s members. Although their lineup is that of a bluegrass combo, the Jades’ sound is generally darker and spookier — sometimes melancholy, sometimes edgy and apocalyptic.

A key strength of the group’s current incarnation is the eerie baritone-soprano interplay between vocalists Kazor and Jennie Benford, both of whom also play guitar and the occasional jaw harp or mandolin. As writers, Benford has a knack for penning new songs that sound ancient (“Can’t Stare Down a Mountaineer” and “One Girl on the Turnpike Road”), while Kazor seems most adept at pushing traditional arrangements into new territory (“Blur” and “Heaven’s Gonna Be My Home”).

Backing them on this album and tour are a solid trio of instrumentalists. Adam Tanner plays slide guitar, mandolin and the Celtic fiddle melodies that anchor many of the songs. Erik Pearson employs banjo, fretless banjo and banjo ukulele to kick up storms of polyrhythmic picking that sound like vintage field recordings. Standup bassist Megan Adie has a background in chamber music and often plays with a bow, which Kazor cites as typical turn-of-the-century practice.

For World’s On Fire, the band made a particular effort to push beyond the simple 4/4 and 3/4 meter of Western folk music and explore the more complex rhythms of Eastern European and African music, sometimes juxtaposing different time signatures within a song.

“I wanted to try to take the music across the Atlantic,” Kazor says. “It was a challenge, but it was a lot of fun, and I think it does give it a kind of otherworldly sound.”

Ironically, given the pains they take to observe tradition, the Crooked Jades get the least respect from Southern audiences, who understandably have strong opinions about their cultural heritage.

“They want old-time music frozen in time, and not necessarily in the ’20s,” Kazor says. “This is frozen in the ’50s and ’60s, when the revival was happening. If you deviate from that, they’re just going to turn their nose up at it.”

The band is looking forward to a four-week tour of U.K. music festivals later this year. Like countless American musicians before them, they generally find a warmer welcome in Europe.

“The reception, the money, the way we’re treated as human beings — it’s amazing how different it is from the U.S.,” Kazor says. “They just don’t have as much prejudice. If it’s good music, they support it.”