Related Clues:

• Sustained hum
• Bor-r-ring voice
• Male in the hive
• Worker bee
• Monotonous speaker
• Annoying hum
• Fail to modulate
• Borrrring voice
• Queen's attendant
• Monotonous tone
• Bee in a hive
• Remote-controlled craft
• Sing sans melody
• Plane sans pilot
• Go on (and on, and on ...)