Related Clues:
- Sing with closed mouth
- Just a tick, not one on the same pitch
- Dull speaker's delivery
- Unvarying voice
- Sound of / droning / on and on, / on and on ..
- Engine room noise
- "Rattle and __": U2 album
- Copier sound
- Carry a tune without words
- Had smash "Stars"
- "Downward Is Heavenward" band
- Droning
- Almost sing
- Good noise from an engine
- Half-cut people murmur