I ran some blind radio scanning on Sabbath's concert in Moscow (2016 The End tour) and captured this fragment. For years i thought that it was live audio from the vocalist's microphone until i started making this video and it turned out that the sound was somewhat different from the performance on stage. But it perfectly matched the videos from the previous show of the tour in Stockholm: most probably it was the live recording transmitted into Ozzy's earphones so he wouldn't forget the words.
Captured with RTL-SDR + SDR Touch Android.
Video footage: ruclips.net/video/INfOKPYAaRM/видео.html .