Beautiful music despite the headaches

Alison Krauss' crystalline voice, simultaneously airy and weighty, lends even the saddest songs - and her new

Paper Airplane

is full of sad songs - a sense of affirmation and pristine beauty. It's Krauss' first album in seven years with her longtime bluegrass band Union Station, and it was one of her most challenging to create, although it doesn't sound that way.

Krauss spent several of those interim years working with Robert Plant and T Bone Burnett on the Grammy-winning Raising Sand. Meanwhile, everyone in Union Station - Dan Tyminski, Jerry Douglas, Ron Block, Barry Bales - continued their flourishing careers outside the band, so scheduling was the album's first hurdle. Once they finally reconvened, however, Krauss was struck by debilitating migraines, which caused her to second-guess her judgment during the recording process. That was particularly difficult since she was returning to the driver's seat as leader and coproducer of the project.

"For the record with Robert, both of us put our gut instinct in the backseat because we needed to, and because we had T Bone. We really wanted to have a different identity for the pairing of us, and we gave up our opinions to make sure T Bone's could be heard," she says from her Nashville home.

But for Paper Airplane, Krauss had to rely on those instincts again, and the headaches left her unmoored. "Everything was so askew because I wasn't well. It was difficult: You don't have as much fight when you're hurting all the time. It's hard to make musical decisions when you're not feeling good."

But the migraines passed ("They have left the building," she says), and she and the band crafted another immaculate collection, with a few scruffy Tyminski vocal turns for contrast.

Paper Airplane supports the title track's decree that "every silver lining seems to have a cloud that comes my way," and Krauss cried when she recorded Richard Thompson's heartbreaking "Dimming of the Day." But that sadness won't necessarily pervade Friday's show at the Academy of Music: Krauss tends to banter and joke with her bandmates when they perform, and she doesn't mind revisiting the album's emotional depths.

"I don't find it draining; I find it healing, if anything," she says. "The songs that don't stay interesting to me are the ones you ended up recording because you thought they were pretty or you thought they were clever. But when they were really a reflection of how I was feeling at a certain time, they never get old."