Robert Plant performing live with his Band of Joy at Hill Auditorium.

Lon Horwedel | AnnArbor.com

Even Robert Plant doesn’t quite seem to know how to label what he’s playing with his new outfit, Band of Joy.

But he seems pretty sure — as did an adoring audience at Hill Auditorium Friday — that, whatever it is, it’s working pretty well for him.

“What a great night,” Plant said as his 90-minute set wound to a close. “You get it. We get it.

“But what is it?”

Good question. In fact, it was a return to Plant’s pre-Led Zeppelin roots, finding the still-golden-haired singer exploring deep American blues, Appalachian gospel and British folk music, with a little low-fi indie rock thrown in amid a handful of Zep classics.

And, for as weird as it was at times, it all worked pretty well on Friday.

It doesn’t hurt that Plant has assembled a world-class band, anchored by the always-amazing Buddy Miller on lead guitar, as well as singer-songwriter Patty Griffin on guitar and vocals and multi-instrumentalist Darrell Scott on just about anything with strings.

Nor does it hurt that, behind those three, Plant might be the fourth best singer in the band.

Robert Plant performing live with his Band of Joy at Hill Auditorium.

Lon Horwedel | AnnArbor.com

But in spite of some occasional pitchiness — and, unfortunately, frequent feedback issues — Plant has a way of making a song his own. Ever the showman, he can sell a song by sheer charisma, even at age 62.

There isn’t much to a lot of the covers Band of Joy tackled. Songs like the rockabilly-tinged “You Can’t Buy My Love” or “Please Read the Letter,” which was culled from Plant’s multiple Grammy Award-winning 2007 record, “Raising Sand,” lack any real hooks and tend to sound same-y as a result. But Plant added a stately grace to even the thinnest of material, whether he was singing or playing sideman to his bandmates by shaking maracas or dancing along.

Miller, Scott and Griffin took solo turns on one number apiece. Miller's was the highlight, benefited by Plant's bluesy harmonica work and Griffin's harmonies.

Plant, likewise, was at his best when harmonizing with Griffin, as he did frequently, or reinventing the gospel standard, “Wade in the Water,” which segued beautifully into the blues standard “In My Time of Dying,” made famous by Led Zeppelin on “Physical Graffiti.”

Not surprisingly, that song and selection of other Zeppelin classics were the evening’s best-received, if most uneven, tunes. “Tangerine,” the “Led Zeppelin III” chestnut, was appropriately twangy, while “Gallows Pole” was as dramatic as ever, although “Ramble On” was a mere shadow of it former self as a vapid, deconstructed folk tune void of any dynamics. But Miller proved that Jimmy Page has got nothing on him during a smoldering reading of “Rock and Roll” that should become the standard by which the song is measured.

Will Stewart is a free-lance writer who covers music for AnnArbor.com.