Related Clues:

• Barbershop parts
• Caruso and Pavarotti
• Many stage Romeos
• Singers producing notes for the audience
• Otello, Don José and Siegfried
• Singers otherwise found in numbers
• Opera heroes, often
• Certain a cappella group members
• Male voices higher than basses
• Singers such as Ian Bostridge and Russell Watson
• Mercury and Mars, for two
• Singers sounded out notes
• General senses
• Singers: one more than nine, otherwise singular
• Barbershop fixtures