Related Clues:
- Refrigerator sound
- Sound of contentedness
- Sound happy, maybe
- Expression of contentment
- Bee sound
- Fake the vocals in Rock Band, say
- Annoying speaker problem
- What you can do if you don't know the words
- "I'm happy" in Siamese?
- Droning sound
- Low, droning sound
- Manx murmur
- Catnap noise
- Sing with one's mouth shut
- Amp problem