Related Clues:

• Jose Carreras, for one
• See 1-Across
• 'Z' preceder?
• Domingo, for one
• Pervading tone
• See 17-Across
• One who sings the part of Boris Godunov
• ___ profundo
• From ___ Z
• Don Jose, in 'Carmen'
• Quarter of a quartet, maybe
• Violist's clef
• Countertenor
• ___ Z (everything)
• Doo-wop part