How does Fitzgerald use auditory imagery in The Great Gatsby?
Most of Fitzgerald's auditory imagery in The Great Gatsby relates to money and materialism. When Nick describes Gatsby's party next door, much of his description relates to the sounds of the party--the music, the voices, and the raucous laughter. The sheer volume of the party combined with the leftover mess the next morning illustrate the excess and debauchery of the wealthy.
Similarly, Fitzgerald's description of Daisy's voice being "full of money" symbolizes the sound of aristocracy. This is partly why Gatsby tries to be so measured in the tone of his voice and his expressions like "Old Sport."