American artists as diverse as Aaliyah, Cassie, and Rockville-raised newcomer Kelela have produced excellent experimental R&B, with the singers’ passionate, blues-based vocals lending the clattering rhythms some earthy balance. But in the U.K., leftfield soul by the likes of The xx, Kwes., and James Blake comes from a more ethereal place, with the artists’ voices drifting through the mix like dreams. Blake’s 2013 album, Overgrown, is still led by his strikingly smooth tenor, but the music is even more subtle, more restrained than that of his 2011 self-titled debut, whose haunted atmosphere was punctuated by darts of dubstep. Overgrown is a slow walk through a graveyard at night after the death of a relationship. There are deep blues here, but they’re ghostly—real emotions presented as apparitions. James Blake performs with Nosaj Thing at 7 p.m. at 9:30 Club, 815 V St. NW. $32. (202) 265-0930.