Audio mixing is the act of summing several participants' audio into a single stream, with level management and limiting to stop the combined signal from clipping. It is the core job of an MCU and of server-side recording, where many talkers must become one coherent track, and it also happens on the client when a layout blends multiple remote streams. Good mixing is more than addition: it manages gain so a loud talker doesn't bury a quiet one, applies a limiter to catch peaks, and often mixes only the few active speakers (chosen via audio-level) to save work and keep the result clean. Done poorly it produces clipping, pumping, or a muddy, fatiguing blend.
