the Metropolitan Opera now has a database of every performance back to 1888 AND sound bytes of performances -- going back to the earliest days of RCA Victrola --
http://66.187.153.86/archives/frame.htm
http://www.metoperafamily.org/metopera/history/sounds/
unfortunately I can't find in the soudn-byte archive the 16 seconds of Monserat Caballe at the end of Don Carlo for which where she brought the house down -- the last performance for Rudolph Bing as Managing Director.
http://66.187.153.86/archives/frame.htm
http://www.metoperafamily.org/metopera/history/sounds/
unfortunately I can't find in the soudn-byte archive the 16 seconds of Monserat Caballe at the end of Don Carlo for which where she brought the house down -- the last performance for Rudolph Bing as Managing Director.