Abstract: A system and method for audio multicast includes a flexible number of active and passive conferencing endpoints in packet communication with a server. The server creates a mixed audio stream from the received audio packets from the active endpoints. The server multicasts the mixed audio to all the conferencing endpoints. The endpoints determine if the received mixed audio includes any self-generated audio by comparing the received packet to a sample packet of self-generated audio stored prior to transmission to the server. The endpoint encodes and decodes its own audio twice to match the transformations that occurred for the endpoint's contribution to the mixed audio. If a match is present, the endpoint removes the self-generated audio from the mixed audio and plays the conference audio.