This year, Alabama Shakes took a quantum leap without ever really leaving home. On Sound and Color, its second album, the band didn't betray the '60s R&B and Southern rock influences of its NPR-anointed 2012 debut, it merely vibed them out—with vibraphone, in some cases—a redesign similar to what My Morning Jacket pulled off with Z a decade ago.

Now, it's reaping the rewards, and the awards, too. On the night it rolled into the sold-out Crystal Ballroom, as part of KNRK's December to Remember concert series, the group learned it had been nominated for six Grammys, including Album of the Year. And it wasn't about to play coy about it.

"I'm not a great public speaker," frontwoman Brittany Howard admitted from the stage, in the heavy drawl of her home state. "So imagine my horror when I heard we were nominated for six Grammys."

It was a well-earned humblebrag. But that doesn't mean the band has nothing left to prove, and it certainly didn't play like it. Adding two keyboardists and a trio of backing singers to the core quintet, the expanded Shakes teased out the details in the smoky funk of "Don't Wanna Fight" and floating soul of "Future People" and brought extra wallop to older songs like "Hold On."

Even while flanked by eight other members, though, the focus remained on Howard. Splicing the DNA of Otis Redding and Sister Rosetta Tharpe, she howled, growled and testified, projecting not just her voice but her facial contortions to the back of the room. Although the set was closed by one too many ballads—which the crowd augmented with chatter that often rose to the level of a dull roar droning under the music—Howard never let the energy lull long, rising from whisper to scream and animating each word with her mouth, and reaching up from her guitar to push back her sweat-slicked glasses each time they reached the edge of her nose without ever breaking rhythm. Maybe she's not much of public speaker, but the performance said all she needs to.