Related Clues:

• The Three ___
• Low strings
• Choir members
• Met stars
• Caruso and Carreras
• Some barbershop quartet members
• High-toned fellows?
• Some male singers
• Courses of thought
• Pavarotti et al.
• Choir section ... and what are missing from the starred clues
• Roy Orbison and Marvin Gaye, e.g.
• Some of the knights in Wagner's 'Tannhäuser'
• Pavarotti and Domingo, e.g.
• Singers above baritones