That sounds like Vladimir Vysotsky’s voice on that tape recorder, though his guitar is not strung as loosely as he sometimes had it. (Click through to go to a YouTube video of this scene, at 6:20). It seems that Ivan Grozny is starting to like to it. (He’s visiting from the 16th century, in the 1973 comedy film, Ivan Vasilievich Changes Professions.)
I presume I’m not catching the entire significance of matching up Vysotsky with the Tsar.