Neither of them ever graced the stage of the Metropolitan Opera, and here they tear through the Gioconda duet and demonstrate the importance of well-developed registers.
La Grunowa agrees:
https://www.youtube.com/watch?v=6zj6TRX1qWE
Ebe Stignani never made it to the Met. Yes, World War II intervened, and she claims in the Rasponi book that the timing was bad and also implies she was never asked as she should have been.
She also claimed in the late 1940s she was performing regularly and happily on the concert/recital circuit in America (an acquaintance of mine heard her in Orchestra Hall in Chicago and she blew the roof off of the place and also sang soprano arias, including “Or sai chi l’onore”!). But for goodness’s sake, the Met (and Toscanini in his NBC performance of Aida — instead, we were subjected to the bizarre casting of the mealy-mouthed Eva Gustavson as Amneris) really needed her.
Maybe they were used to more glamorous mezzi like Stevens or Swarthout, but in the dramatic mezzo repertoire, Castagna retired and Elmo’s top was already disintegrating. And maybe they were used to soprani as Santuzza as well (Milanov, Roman et al.). And the young, vibrant Fedora Barbieri was certainly a rival, but her extreme top notes were already flatting.
