In one embodiment, a network interface broadcasts an audible message from a first computing device to a plurality of second computing devices over a first channel. The audible message comprises an audible noise broadcasted using a plurality of frequencies and a first unique identifier indicative of the first computing device. The network interface receives an acknowledgment message from each of the plurality of second computing devices over a second channel. A processor identifies each of the plurality of second computing devices based on the second unique identifier in the acknowledgment message and initiates a collaboration session between the first computing device and the plurality of second computing devices by sending a collaboration message from the first computing device to the plurality of second computing devices. The collaboration message automatically causes the plurality of second computing devices to enter the collaboration session.