While it may be wrong to judge a book by its cover, it's something that happens. You see a person, you expect certain things. This extends even to their voice. If you see a muscular man, you expect a deep macho voice. The Vamp will have a sexy, sultry voice. A child's voice is high pitched. And so on. This trope is about when those expectations don't match up. For when the muscular man has the sultry voice, The Vamp has the childish voice, and the child has the deep macho voice. Examples of Vocal Dissonance include: