If you've never seen someone headbang to a mandolin, go see Robert Plant and Alison Krauss. The pair have successfully married their sounds in a way that not only casts Plant's old work in a new light

If you've never seen someone headbang to a mandolin, go see Robert Plant and Alison Krauss. It didn't occur often during the duo's twenty-two song set, but some fans just couldn't resist during a stripped down version of the Led Zeppelin classic "Battle Of Evermore." And strangely, the headbanging didn't seem out of place. Plant and Krauss have successfully married their two sounds in a way that not only casts Plant's old work in a new light, but that also opens Krauss's down home style Americana to a new audience.

The pair has been on tour for awhile now, and they've managed to perfect a father-daughter style stage presence. Plant, 59, often looked at Krauss, 36, in a proud, "that's my girl" way. She commanded her voice at peak moments during "Through The Morning, Through The Night" and the traditional "Down To The River To Pray" in ways that Plant didn't. At this juncture, Plant is quite comfortable with a mostly subdued presentation and with showing the adulation he has for the angelic sounding Krauss.

Aside from a slow, back-porch stomp version of "Black Dog," and a few T-Bone Burnett tunes, it was the material from their acclaimed 2007 album, "Raising Sand," that Plant and Krauss showcased. Opener "Rich Woman," suffered a bit from a muddy sound mix, but things quickly picked up with the banjo based "Sister Rosetta Goes Before Us." The Page / Plant penned "Please Read The Letter" captured Plant's voice in a quiet, hushed way that Krauss augmented with her fiddle and her subtle, unpretentious delivery of the chorus. "Killing The Blues" also highlighted their connection; most of the night they stood ten feet from each other, but for this song, they stood only apart with their voices bonding tenderly.

Following the song, Plant paused to tell the crowd a brief history of his relationship with American music. "I was blind...but now I'm still blind," he joked, as he mentioned how much new music Krauss and her companions have turned him on to, including the late, great Townes Van Zandt. It was during their version of Van Zandt's "Nothin'" that Plant turned in his best vocal of the night as he showed off his range by moving between high notes, low notes, and scatting. Plant's delivery of this otherwise obscure tune surprisingly outshined any of his Zeppelin material that night.

And that's what should be the selling point to these two; they're both proven masters of their respective genres, genres that a lot of people probably didn't think would meld so well together. But Plant and Krauss know their histories well enough to make an old bluesy rock guy and a country gal rooted in gospel seem like they were meant for one another.