@danager. Re:clip of Tebaldi and Callas. Well you tried. More than that I cannot ask of any man. Or woman. They do say that the fastest way to empty a room at a hifi show is to put on some opera.
Tebaldi was technically superior to Callas. Tebaldi was smoother and in this clip you can clearly hear the crackling in Callas voice as even her most ardent fan will admit. Yet with her more limited voice, Callas conveys more heartfelt emotion. I can't explain in a technical way how she achieves this, not being a singer. Her fans just know it as the Callas Magic.
The scene is from Puccini's Tosca with Tebaldi and Callas in the title role. Tosca is being seduced by the chief of police in exchange for the release of her lover from prison and torture. Here she mourns her predicament in the song I Lived for Art - Visse d'Arte singing that she lived a life of innocence dedicated to her craft.
In reality, Callas lived the life being partnered to the boor Aristotle Onassis who didn't appreciate her singing. He once questioned why she continued singing since he had enough money for both of them. (You may remember him for marrying Jackie Kennedy. It was considered scandalous at the time for a former First Lady to marry for money. Ted Kennedy brokered the deal in person.)
In the opera, Tosca stabs the chief of police to death rather than submit to his blackmail. I always imagine Callas is thinking Take that, Onassis! as she plunges the scissors into her fictional foe so convincing is she in that role.
