Possible Clues:

• Low male voice
• Low-voiced operatic singer
• Bartolo in 'The Barber of Seville,' e.g
• Bartolo in "The Barber of Seville," e.g
• Instrument not working for Italian singer
• Lowest male singing voice (sometimes 'profundo')
• Every other member of Abba uses low singing voice
• Rossini's Doctor Bartolo, e.g
• Word before continuo or profundo
• Singer wants musical instrument? Not on!