Related Clues:

• Run well
• Sound of tires on the highway
• Soporific delivery
• Machine sound
• Make music, in a way
• Sing, in a way
• Electronic noise
• Substitute for forgotten words
• Unvarying in pitch
• Sing wordlessly
• Participate without the lyrics
• Dull voice
• Sound system problem
• Theme, Part 2
• Unpleasant smell