Say this for Daniel Barenboim: he’s never boring. The celebrated conductor/pianist may not have the youthful sheen that once added to his stardom, but his controversial involvement in Mideast politics and his outspoken opposition to America’s near-constant use of music as background noise make him one of the era’s best interviews. These days, Barenboim is on a lecture tour of three continents, and he is taking seemingly everyone to task: Americans for their short attention spans, Germans for being unwilling to accept the unpleasantness of their own history, Britons for allowing music education to decline precipitously, and Israelis for their seeming inability to differentiate between power and strength.