The director uses both diegetic and non-diegetic sound to emphasise the themes in the film. The sound is designed to follow the main character Katniss Everdeen subjective to emphasise that we are experiencing her point of view. When the sound goes quiet or extra noisy it is to emphasise what she is experiencing in that moment.
For Example: When Katniss enters the tube to take her to the Cornucopia, at the start of the games, there is a diegetic (which means it is part of the story) sound resembling a vacuum closing, that suggests she is being sucked into a black hole. When she comes up the tube and in to the Cornucopia there is a loud electronic sound that echoes her hysteria at this moment. The sound reflects her state of anxiety.
The dip in sound that is experienced during Katniss’s first interview with Caesar Flickerman shows her lack of engagement in what he is saying, to emphasise she is feeling overwhelmed by the watching audience.