TAOS, N.M. — A rectangular medallion swung from the rearview mirror of Brittany Howard’s car as she steered a scenic drive — through mountains, desertscapes, forests and gorges — around this high-altitude city she calls an “energy epicenter,” her home since December.

It looked like the kind of locket that holds the image of a saint. But up close, it was a faded photograph of two young girls, both in red home-sewn clown costumes. One was a very young Howard; the other was her older sister, Jaime, who died at 13 from retinoblastoma, a rare form of childhood eye cancer; Howard was just 8 years old. During Jaime’s illness, the family’s house burned down, and the photo is one of Howard’s few keepsakes of her sister. “I take it with me everywhere,” she said.

“Jaime” is also the title of Howard’s solo debut album, due Sept. 20, as she steps out from Alabama Shakes, the Grammy-winning soul and rock band she has led for most of this decade. “Jaime” memorializes the sister who was Howard’s role model as a musician, writer and more. “She was a thinker,” Howard said. “She was a creator. She was just immaculate, just genius-level stuff. She taught me that if it don’t feel right, that means it’s not right. She taught me everything about everything.”

But in a statement about “Jaime,” Howard wrote: “The record is not about her. It’s about me.” It’s simultaneously more personal, more socially conscious and more unruly than her albums with Alabama Shakes. The songs are funky, experimental, rowdy and exposed: the work of a songwriter going deep to explore spirituality, sexuality, traumas of the past and ideas about the present, by way of danceable propulsion and sonic escapades. It gleefully ignores conventions of genre, structure and texture, sparse at one moment and wildly overstuffed the next.