Processing Noise Cancellation - Polycom SoundStructure C16 Design Manual

The room gain is shown graphically in the meter and the number in the box next to the meter. Room gain is
defined in more detail in
dB. See Installing SoundStructure Devices
The AEC references for each input are specified in the pull-down combination boxes for the associated input
signal. As described in the
the entire virtual channel group and that information propagates to all the virtual channels of the group.
Input Signal AEC References
You can select references from any output signal or from any submix signal. A reference can either be a
mono virtual channel or a stereo virtual channel. If you specify only a single mono virtual channel reference,
the system operates as a monaural echo canceller. If you specify either a stereo virtual channel or two mono
virtual channels, the system operates as a stereo echo canceller.
References need to consist of all the remote audio that is being played into the local room including
telephony signals, video codec signals, and program audio.
Note: Using Output and Submix Signals as Echo Canceller References
You can use any output signal or submix signal as an echo canceller reference. The
reference needs to include all remote audio sources.

Processing Noise Cancellation

The noise cancellation processing is available on all analog inputs via the conferencing and sound
reinforcement processing paths. The noise cancellation reduces background noise that is picked up by
microphones or already present in input signals from program audio sources. You can turn the noise
cancellation functionality on or off with the enable button and adjust the amount of noise cancellation c from
0 to 20 dB.
The SoundStructure noise cancellation effectively removes different types of background noise ranging
from narrow band noise (e.g., tones) to broadband noise. For best performance, the noise characteristics
need to be quasi-stationary. For example, the statistics of the underlying noise are fixed or change slowly
over time.
You can enable noise cancellation for a non-microphone channel, such as a video codec audio or program
audio, by selecting the conferencing version of the ungated signal path. Note that the default selection for
non-microphone audio sources is the line-input processing path.
Polycom, Inc.
Appendix B: Address Book. The display of room gain is limited from -10 dB to +20
for additional information on room gain.
Creating Virtual Channel Groups section, you can select the AEC reference for
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