If you thought Bach’s six Brandenburg Concertos demand Teutonic seriousness, think again. Rinaldo Alessandrini, directing his virtuoso Concerto Italiano from the harpsichord, brings a Mediterranean warmth and verve that reveals how much Bach drew from his Italian contemporaries. Solo lines emerge with clarity but also with terrific energy, and the ensemble passages fuse animation and order with winning results. In these six concertos—no two scored the same—Bach threw down the gauntlet and, in doing so, invented a musical language. There are dozens of fine recordings, but Concerto Italiano’s, from 2005, is one of the finest.