10. Hedley
9. City And Colour
8. Adam Lambert
7. Lady Gaga
6. Kelly Clarkson
5. Marianas Trench
4. Beyoncé
3. Christina Aguilera
2. Mariah Carey
1. Adele
Beyoncé has a much larger and overall better voice than Adele but the list did say "Biggest Voices". Adele may not have much of a range but her voice is hella powerful.