Too few clues to their mysteries

The Fiery Furnaces

“Rehearsing My Choir”

(Rough Trade)

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THIS Brooklyn-based brother-sister duo has never tried hard to make things easy for listeners, constructing phantasmagoric futurist-folk-flavored epics that challenge you to penetrate their private world.

It’s been a fairly rewarding endeavor in the past, but Eleanor and Matthew Friedberger hit a wall here in their fourth album, an ambitious account of their grandmother’s apparently colorful life that remains frustratingly lifeless.

In typically unconventional fashion, the team frames “Choir” much like a radio documentary, with 83-year-old Olga Sarantos herself providing much of the story in a spoken narrative. With her deep, raspy voice, she sounds disconcertingly like a mix of Crispin Glover and Tiny Tim as she remembers youthful love and infidelity, difficult relatives and lonely journeys.

There might be a compelling story in there, but when the Furnaces’ songs come in to elaborate on her tales -- Eleanor sings in the role of other characters, and the story spins into surrealism -- it’s all but impossible to figure out what’s going on. And that makes it hard to care.

Albums are rated on a scale of one star (poor), two stars (fair), three stars (good) and four stars (excellent). The albums are already released unless otherwise noted.