re: The man in black

Cash had by far the most potential in his voice than the rest in the group.

You don't hear very many low baritones/high basses that are in contemporary mainstream music today, Josh Turner comes to mind and he was the biggest country music star for a short time.

Cash didn't take voice lessons that could have strengthen his voice and bring out his full potential.

Bill Medley who has a similar voice type to Cash did admit to taking voice lessons and his voice is elite.