Answer and Explanation:
The poem's first stanza shows how the environment was affected by the music the man played. In the second stanza, the poem shows all the melancholy and sadness in the music that the man sang, but somehow, the reader can see that music is a way of expression for this man, it's the way he puts these sad feelings out . Thus, the contrast between these two stanzas show how the man who is very sad about his own life, feels better after singing, because the music relieves him.
This reinforces the overall theme of the poem. This theme shows that melancholy, loneliness and sadness can be lightly relieved through music and artistic expression.