Jacket: Band’s heart’s on its sleeve

My Morning Jacket has used 2008 to establish itself as limitless free-spirited rock ’n’ roll saviors. It’s been a decade of gradual transformation for the five-piece outfit originally hailing from Louisville, Ky.

The group started as Southern garage rockers with a few indie leanings and an ability to touch down into sincere rural melancholy. Frontman Jim James has said that his band’s early direction stemmed from him listening to Neil Young’s “Harvest,” and the influence was obviously initially strong. But since 2003’s “It Still Moves,” which was the group’s strongest effort in the vein and its first on the locally based ATO Records, the band has moved into a new realm of sonic experimentation.

It started with 2005’s “Z,” which dabbled in trippy reggae, but it’s been increasingly expanded with this year’s critically hailed “Evil Urges.” The latest disc seems intentionally to avoid boundaries as it bounces around from disco funk to R&B grooves, along with the expected harder dirges and psychedelic country ballads.

On the title track James lets his vocal get even further away from the tunnel-effect reverb that he favored on earlier discs, and he instead tries a sunny Prince-like soul inflection that floats above swirling distorted guitar licks.

“I’m Amazed” is a soaring straightforward big-chorus, note-lingering stadium thrasher, while “Sec Walkin” manages to conjure some steel-driven Nashville sadness and some “O-o-h Child” optimism in the same song.

The boldest song on the disc, though, is the eight-minute “Touch Me I’m Going to Scream Pt. 2,” which bursts out of a spacey keyboard intro into a suggestive ’70s dance party with James pushing the erogenous zone of the chorus: “This feeling is wonderful, don’t you ever turn it off.”

The evolution has enabled My Morning Jacket to hone its well-reputed live show into epic arena territory.

It’s been displayed this year with a widely buzzed four-hour set at the Bonnaroo Music Festival and at the beloved Red Rocks Amphitheatre in Colorado, and it will culminate with a New Year’s Eve performance at Madison Square Garden.

The band plays the Charlottesville Pavilion on Thursday night.

My Morning Jacket: Five Fast Facts

l In 2005 My Morning Jacket was forced to cancel a New Year’s Eve appearance opening for the Black Crowes at Madison Square Garden in New York City after front man Jim James came down with pneumonia.

l According to a story in Rolling Stone, the name My Morning Jacket comes from a discarded coat James found that had the letters “MMJ” on it.

l This year the band will get a redemption shot at New Year’s Eve as a headliner at Madison Square Garden.

l The band made an appearance in the Cameron Crowe film “Elizabethtown,” where they covered “Free Bird.”

l Another highlight of the band’s huge 2008 was a four-hour midnight set at the Bonnaroo Music and Arts Festival in Tennessee. During the show the group shared the stage with Metallica guitarist Kirk Hammett and played 35 songs, included some unexpected covers including Sly and the Family Stone’s “Hot Fun in the Summertime” and Motley Crue’s “Home Sweet Home.”