"Even though I'm a metal singer, the fact that I’ve been able to appreciate other types of performers has probably paid dividends. When I listen to Michael Buble, it's exciting, it's inspiring. I feel the same way with Michael Feinstein or Ryan Adams. I'm drawn to singers who have something different to say vocally - and Adele would be in there. I saw (Barbra) Streisand in Phoenix and that was mind-blowing. Her voice is just so pure. I've also always had a passion for some types of opera... I sing Nessun Dorma when I warm up backstage." Judas Priest frontman Rob Halford enjoys listening to the world's great voices.