Agree, singers usually found out when they perform live, Freddie the best for that although I went with Hucknall as he the best I heard actually live.I think what I admire the most is their ability to sing live and without editing to a standard that still sounds wonderful, without the need for all the technology.
If you think of Mercury at Live Aid, with all the pressure and ambient noise, and he smashes it live in front of a huge crowd. That's a star in my eyes!