Answer:
- The low note was a grunting, a rumble, the deep discordant growling of an ill-conditioned dog.
- Then suddenly the singer threw up his face, straightened his tubby figure...
- Many a singer far better than this absurd fop ....
In the first sentence, the mocking tone is conveyed by comparing the low note of the lyre to the unpleasant growling of an angry dog. It is also said to be a "rumble" and a "grunting." It is making fun of the lack of skill of the musician.
The second sentence mocks the singer. His voice is as bad as the sound of the lyre, resembling the growl of a dog that has just been kicked. His appearance is similarly funny, with a "wagging head" and "scarlet cheeks."
Finally, the third sentence mocks the singer by calling him an "absurd fop."