Joy Williams and John Paul White aren’t a couple, but they certainly sound like they’re in love, singing together with the sort of familiarity that only seems to exist between couples and siblings. On Barton Hollow, their studio debut as the Civil Wars, the two trace each other’s melodies with close harmonies that never fail to lose their romance, even on breakup tunes like “Falling.” It’s an organic, folk-pop sound not unlike the one made by the Swell Season, another boy/girl duo with a talent for making heartbreaking Americana. If the Civil Wars are America’s answer to that band, then “Poison & Wine” is their “Falling Slowly.” An aching, gorgeous tribute to a relationship on the rocks, it’s one of the few tracks to include more than an acoustic guitar, with some piano and soft drums also making their way into the mix. Even so, the focus remains on the band’s vocals, which are easily the best instruments on Barton Hollow. Those who don’t like rootsy ballads are in for some slim pickings, since Barton Hollow shines its brightest whenever the tempos slow, the lights dim, and the voices rise up. But the title track, with its outlaw lyrics and swanky Southern groove, is a nice change from the norm, and “I’ve Got This Friend” finds a balance between both camps. Good stuff.