In The First Emperor the prompter could be heard shouting by the audience in the theater. This creates the impression that Placido's hearing may not be the best. This reminded me of my own life in the theater, such as it was, when I can truly say that I never heard the prompter who worked every performance sitting in her chair by the side of the stage.
One of my companions said she also heard prompting for the tenor in I Puritani.
5 hours ago