The blues has a hold on a lot of musicians, but rare is the musician who has a hold on the blues. Case in point: Gary Clark Jr., the pride of Austin, Texas, who plays to softly wake the sleeping ghosts of the Delta, then shake them out of their graves with a killer Jimi Henrix-style guitar and rock ’n’ roll wail. But don’t be mistaken — Clark is a traditionalist in the sense that his blues are a progression of the genre, and not a distillation. While bands like The Black Keys weave in those weeping 12 bars and build from there, Clark never strays so far that you’d forget his roots but tweaks just enough to be purely modern. Michael Kiwanuka, on the other hand, brings old-school Detroit soul via England, with a voice as smooth as Sam Cooke and a groove straight from Motown, interpreted in the way only a Brit-via-Uganda raised on Nirvana and Radiohead could.