Polycom SoundStructure C16 Design Manual page 437

By default the two telephone lines are routed to both "Amplifier 1" and "Amplifier 2" and the stereo program
audio "Program Audio" channel is routed as a mono signal to both Amplifier 1 and Amplifier 2 as shown in
the next figure.
Matrix Project Window.
To create the positional solution, route one telephony interface to one amplifier and route the other to the
second amplifier. Also, we'll make the assumption that each amplifier should receive one channel of the
stereo program audio. The mapping of the stereo program audio signal to the mono amplifier outputs can
Polycom, Inc. 437