The internal earpiece (top speaker) allows you to hear the person you are talking to. It needs to be replaced on the Samsung S21 Ultra if it crackles or no longer emits any sound.
This internal earpiece (top speaker) generates the sound of the person you are talking to during a call.
Here are some signs that indicate it needs to be replaced:
Replacement is very simple and takes about 15 minutes; no repair knowledge is necessary.