Atlanta impresario Bradford Cox is correct in singing that “Darkness doesn’t always make much sense,” and that’s apparent in the composed freakiness of Halcyon Digest. His is a varied palette: After the cataclysmic crunch of opener, “Earthquake!,” the menu meanders from the jangly upswing of “Revival” and “Memory Boy” to the stark falsetto of “Sailing.” Garage rock give way to the ’50s clap-tastic, straight-from-a-“Happy Days”-episode joy bomb, “Basement Scene,” which is underpinned by a mesmerizing, kaleidoscopic drone. “Desire Lines” stands out as the shimmering centerpiece that hinges upon a revolving guitar figure that creates a pleasant, transfixing wave. Cox and crew snap you out of it on “Helicopter,” with a backbeat forged out of a kind-of synth harpsichord and drip-drops from a drum machine. If you’re bored by this one, you only have yourself to blame.