The seven members of Amabutho came out of the cast of the South African musical Umoja, and their album has a musical’s sleek professionalism. It’s as trim as their beards. Overlapping lines of blobby alto clonk roll deftly out of their marimbas. The lead singer calls and the male mass responds with the come-and-go tidal heave of an isicathamiya chorus. A man whoops and whistles. Every note rings so neatly in place that you feel you could reach into the song, pick it out, and exhibit it as a prime example of a well-tended, well-fed note, not too loud, not too soft, just right. An album of disciplined rhythmic force.