Review: Chemistry of Plant, Krauss clicks again on follow-up

“Raise the Roof,” Robert Plant and Alison Krauss (Rounder Records)

Pairing Alison Krauss’ angelic soprano with Robert Plant’s roguish tenor once sounded like a bizarre idea – until they started to sing together. The improbable partnership produced the hit album “Raising Sand” in 2007, and their chemistry clicks again on the long-awaited follow-up, “Raise the Roof.”

Plant and Krauss stick to the formula that worked before and still ignores pop trends. Producer T Bone Burnett returns to oversee spare, rootsy arrangements and direct a stellar supporting cast that includes guitarist Marc Ribot, drummer Jay Bellerose and Krauss’ brother, bassist Viktor Krauss.

The songs are again an eclectic collection that includes covers of obscure rockabilly, country and folk tunes, with sources ranging from the Everly Brothers and Allen Toussaint to Calexico and Merle Haggard.

Krauss and Plant focus on love and loss, with death a recurring character. “Leave me out, let the buzzards eat me whole,” they sing on “Last Kind Words Blues.”

In spite of the album title, ex-Led Zeppelin frontman Plant lets loose only occasionally. The strongest echoes of his former band come on a delightful rendition of the Pops Staples gospel tune “Somebody Was Watching Over Me,” pushed along by Jimmy Page-style guitar that lingers at the end.

But it’s the vocal mix that leaves a lasting impression. Harmony involves difference, and as Krauss and Plant draw on their disparate backgrounds in bluegrass and arena rock, what emerges is a musical marvel. Singing together at the end of the British folk tune “Go Your Way,” they each squeeze 12 notes from a single syllable, finding beauty even in the word “woe.”