Kings of Leon has mellowed out.

With their fourth album, “Only By The Night,” the Followill boys have recorded a mix of Allman Brothers and Coldplay-esque tracks to show a noctural, more reflective side.

The album opens with the brooding “Closer.” Electric guitars are back in full swing, but they’re used in a minor key to contrast the otherwise cerebral sound of the first track. On first listen, it borders on clashing discord, but eventually flows into itself.

“Crawl” comes next, sounding more like U2 than freewheeling rock. Immediately, it’s evident the boys are expanding their repertoire to include a more electro-centric wall of sound.

“Sex On Fire” is the clear single from “Only By The Night.” Caleb Followill’s vocals carry this track, making it one of the only songs still belonging to the Southern rock genre in which the boys originated. This track, while arguably the best on the album, still lacks the hardcore jamming sound of “Taper Jean Girl” or “Razz” from their sophomore album “Aha Shake Heartbreak.”

“Use Somebody” is the next likely single. It too, emits a wall of sound. While beautiful, Followill’s vocals are the only aspects that still sound remarkably like their previous work. This song sounds more like a Brian Eno-produced Coldplay.

After track five, “Manhattan,” the album never picks up again, except with the closing guitar riff on the brooding, difficult “Be Somebody.” The track comes after the raunchy lyrics of “I Want You,” probably a skillful ordering to let the audience know the high of the album is coming down.

The CD ends with melancholy “Cold Desert,” leaving the album’s narrator alone and reflective and sums up the album well.

“Only By The Night” was not the raucous, ramshackle fourth album Kings of Leon could have put out. Undoubtedly, the boys adopted a new sound into their group identity. They’re not the same band; they’re exploring.

The Southern raunchiness in which they introduced themselves to the music scene barely ekes its way out on this album. Reflection and reverence take center stage as well, likening the album more so to “Because of the Times” than to “Aha Shake Heartbreak” or “Youth and Young Manhood.”

It’s kind of a bummer.