This broadcast shows us what Maria Callas was like, midway through her career.  Her use of the words is the most evident thing to me, listening sixty years after the fact.  Also in the cast are tenor Giuseppe Campora as Edgardo, baritone Enzo Sordello as Enrico, and bass Nicolai Moscona as Raimondo.  In the picture is Thelma Votipka, Alisa for the production.  A very young James McCracken is the Normanno.