So we’ve seen the last of the great studio opera recordings. But maybe there’s something new to be made of the live recording. “Think of all those bootlegged accounts of Maria Callas that once surreptitiously circulated among fanatics. More recently, EMI has been legitimizing those recordings and releasing them, sonically cleaned up as much as possible, in its comprehensive Callas Edition. But through the years there have been many distinguished, well-engineered and perfectly legal live recordings of operas.”