Wye Oak look a lot like other boy-girl indie-rock duos. She’s up front singing, he’s in the back pounding away on various instruments. But they don’t sound much like other boy-girl indie-rock duos. For one thing, Jenn Wasner and Andy Stack don’t play twee indie-pop. Instead, their music rolls onto a folk-influenced path that often halts for luscious dreamscapes along the way. On their third album, Civilian, the Baltimore duo turns melancholic, checking in with a set of songs about death and isolation. They’ve also opened up their sound more, revealing new layers of beautiful noise on “Two Small Deaths” and the title track. But without the sugar-rush bounce of, say, Matt & Kim, Wye Oak’s sleepy songs begin to plod after a while. Civilian never rushes forward. It’s more like a slow, sad crawl.