Related Clues:

• Drone sound
• Sound of vibrations
• Emulate a blender
• Buzz kin
• Soft swishing sound
• Machinery sound
• Make a humming noise
• What rotors do
• What helicopter rotors do
• Electric fan noise
• Rotor sound
• Rotation noise
• Machinery noise
• Sources of whisper, hushed, in Rolls Royce? Sound of engine
• White noise from a fan