This was originally shown with another announcer's voice heard. Martin Bookspan's announcements are heard only on the 1990 videocassette release.
This particular concert was originally a two episode broadcast, as were all of the Toscanini NBC Symphony radio broadcasts of operas. Acts I and II of "Aida" were broadcast as Part I of the opera, and Acts III and IV were broadcast one week later, as Part II. Toscanini's programs usually ran no more than an hour or an hour and five minutes. For broadcasts of Beethoven's Ninth Symphony, and for his NBC Symphony opera broadcasts the hour was lengthened by only fifteen minutes, so all of the operas had to be broadcast in two separate installments.