Polycom C16 - Manual (Page 316)

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12
10 - 8
the following figure. The result of this is that the proper signal levels are pre-
sented to the echo canceller and the output signal levels are attenuated
appropriately.
The Local People Hear Echo Of Their Voices From The Remote Room
This problem is most likely with the remote room’s acoustic echo canceller.
Have the remote participants mute their microphone to see if the echo is
removed, if so, troubleshoot the remote room’s AEC by following the instruc-
tions given previously. For remote people follow the instructions for The
remote people hear echo of their voices from the local room issue described above.
If muting the remote participants microphones did not remove the acoustic
echo issue, then check the routing of the remote audio matrix to ensure the
audio from the local room to the remote room is not being sent directly back
to the local room.
Room Gain Is High - What Does It Mean?
Chapter 7 discusses room gain and what the acceptable and expected levels
should be for ceiling microphones vs. table microphones. Room gain above
+10 dB should be reviewed to ensure the input gain on the remote audio
sources is high enough to get the remote sources to the 0 dBu nominal signal
level expected by the SoundStructure devices.