Related Clues:

• Monotonous (or rhythmic) sound
• Extremes of hunger involved in stomach rumbling?
• Engine room noise
• "Rattle and __": U2 album
• Copier sound
• Carry a tune without words
• Had smash "Stars"
• "Downward Is Heavenward" band
• Almost sing
• Make a rhythmic hum
• Good noise from an engine
• Raindrops sound
• Half-cut people murmur
• 'E' missing from the suspect's tattoo
• Refrigerator noise