With influences as far ranging as Neil Young to Pink Floyd, you could call My Morning Jacket many things. Its members hope “jam band” isn’t among them.

“Yeah, there’s a bit of a freedom we have when we play together, and we aren’t rigid in how we play the songs … but I don’t understand why people call us a jam band,” keyboardist Bo Koster said. “I think it’s just improvisational. We do that here and there, but we stick to arrangements for the most part ... that line is just tiptoed.”

Led by mastermind Jim James, they have become legends of the stage with wild, unpredictable and, most fittingly, epic live sets, some as monstrous as nearly four hours. Crowds have swelled accordingly, as have sales; this year’s “Circuital” is its highest-charting to date.

“It’s hard to quantify why those things happen, but our growth has always been a steady climb,” Koster said. “No one thing has helped us more than another. I hope that it’s that the music is getting continually better, and that’s what keeps us relevant.”

Fans may or may not argue that point; the momentum from 2003’s “It Still Moves” and 2005’s “Z” saw a hiccup with the hot-and-cold reaction to 2008’s “Evil Urges,” My Morning Jacket’s most deliberate and grandiose album to date.

By comparison, “Circuital” is appropriately raw and literally unrehearsed, half-baked in a makeshift recording space in a church gymnasium.

“When we went into record, we didn’t have any goals set in mind. It was 12 or 13 days in July, so fucking hot with 100 percent humidity and no air conditioning,” Koster said. “It was no more than riffs or demos, and we came out with about half the album. We’re proud of that.”

Fans can expect new material soon, with a Christmas-themed iTunes release to be unwrapped in short order. The gift took just a day to record, but Koster said the group marvels at how impressive it sounds.

“It exceeded all expectations,” he said. 2012 will be “a victory lap” for My Morning Jacket as it trots across the globe with the possibility of recording lingering toward year’s end. Until then, the splendor of the live performance will more than suffice.

“It’s a lot of fun. I believe in what we are doing,” Koster said. “I feel like we try to be honest with what we do, and every night is an honest portrayal of who we are and what we are inspired by.”

Photo by Danny Clinch