Polycom SoundStructure C16 Design Manual page 111

filter bandwidth from 0.03 to 1 octave and the filter depth from 0 to -100 dB. When enabled, the user
interface displays the FBE as enabled, as shown in the following figure.
Feedback Elimination Enabled
Selecting Edit opens the equalization user control where parameters for the feedback eliminator are
specified, as shown in the following figure.
Feedback Elimination Parameters in the Equalization User Control
There is a safe mode attenuation that defines the amount of attenuation that are applied to the signal if the
feedback eliminator filters are all engaged and there is still feedback. The safe mode attenuation can be set
from 0 to 20 dB of attenuation and have a default value is 3 dB.
The Filter Decay control allows the adaptive filters to relax as the feedback is reduced in the system.
During operation, if persistent frequencies appear, you can fix the filter settings from those offending
frequencies by clicking Make Fixed. This transfers the settings of the adaptive filter to one of the fixed
parametric filters.
Polycom, Inc. 111