Johann Sebastian Bach’s immensely complex exploration of the fugue was left incomplete at his death in 1750, but he still left 14 fugues and four canons, and they’ve fascinated performers ever since. Much of the intrigue lies in the fact that Bach left no specified instrumentation, so it’s up to the musicians to decide on the forces they’ll use. Ottavio Dantone opts for a period-instrument chamber orchestra and conjures up an authentic sound world that does this infinitely rewarding score great justice.