Several effects are achieved in this scene. Willy's professional stature is brought light, Howard's happiness is juxtaposed to Willy's misery, and Willy's self-control is demonstrated as being extremely weak.
Willy meets with Howard with the intentions of getting a transfer. Howard does not give Willy a "proper audience" and instead tries to avoid discussing Willy's problems. Though Howard may do this in order to postpone firing Willy, he is pressed ultimately to terminate Willy. The audio player used in this scene serves to raise the tension of the moment, making Willy ill-at-ease and disturbing Willy's intentions.
Howard wants to avoid Willy and focus on a lighter subject. The fact that he can ignore Willy by choice indicates Willy's low status in the business.
Listening to the voice of his child, Howard is shown in his happiness. This happy diversion from the rather serious and desperate issue in Willy's mind creates a stark juxtaposition and articulates Willy's difficulties.
Given these challenges to his goal, Willy loses control of himself and yells at Howard, his boss. The disruption of his intentions made by the audio player can be seen to help lead to this end.
By placing the importance of the recorder above Willy’s need to speak with him, Howard illustrates that he perceives Willy as insignificant. Quelling his desperation, Willy patiently engages himself by demonstrating interest as he listens to the recordings of Howard’s family. By indulging Howard, this is an opportunity for Willy to bond with him, in turn gaining Howard’s sympathy toward his plight and making Howard receptive to accommodating him. While listening to the voices on the tape recorder, Howard points out that his daughter is crazy about him and that his son has great potential. This is poignant from the standpoint that it is reflective of how Willy’s own children once felt about him and the potential he saw in them, particularly Biff. Willy feels that once he has listened to Howard’s recordings and demonstrated a distinct interest in them, as well as the recorder itself, he will have Howard’s undivided attention. Unfortunately, Willy’s efforts result in solidifying the fact that he has become ineffectual and he is no longer of any use to the company.