Small pleasures — which John Mellencamp has provided sporadically since his mid-’80s consciousness-raising, save-the-farm heyday — abound on what initially sounds like a tossed-off album of acoustic covers. Recording quickly, with no overdubs, Mellencamp injects 12 blues, folk and Tin Pan Alley antiques with off-the-cuff immediacy. The ultra-earnest songwriter sounds juiced by these dirty grooves: He brings out the lasciviousness in Robert Johnson’s “Stones in My Passway” and the Cajun flavors on an accordion-driven version of Lucinda Williams’s “Lafayette.” Nearly worth the price of admission by itself is the moment when Mellencamp rasps “I like to ruffle his plumage” on Hoagy Carmichael’s “Baltimore Oriole.” Mellencamp’s arena-rock plumage gets mussed as well on this, his most intimate recording yet.