Extron Electronics DMP 64 User Guide - Manual (Page 47)

Feedback Suppressor (FBS)
The Feedback Suppressor is used in live situations when there is an indication of
feedback during live operation. Dynamic filters automatically detect feedback on a
live microphone channel, and engage a set of up to 5 fixed and 15 dynamic filters to
counteract frequency peaks at the detected feedback frequency. Up to 15 separate filters
can be employed at any time. The 15 filters act in a FIFO (first in, first out) rotation. If all 15
filters are employed when an additional feedback frequency is detected, it overwrites the
first detected feedback frequency and so on.
To avoid a new feedback frequency overwriting a previously detected one, up to five of the
dynamic feedback frequencies can be placed into fixed filters. Once written into the fixed
filters, the feedback frequency can only be overwritten by the user manually writing a new
frequency to the filter.
The FBS dialog box has three tabs;
Settings , Dynamic Filters and Fixed Filters .
Global settings and view options are controlled from the Settings tab. Dynamic to
fixed filter allocations are handled from the Dynamic filters tab. Filter parameters can be
modified from the Fixed Filters tab.
The FBS Dialog box provides the following global buttons:
• Clear All — Clears all dynamic filter settings.
• Lock — Locks the dynamic filters to the current settings, preventing automatic
updates. This temporary mode is useful while testing the system, or during the time
when dynamic filters are being converted to fixed filters. When the FBS display
window is closed, lock mode is automatically disengaged.
• Bypass FBS — Turns off feedback detection when engaged (button is red). Only the
dynamic filters are bypassed. Fixed filters remain active.
• Set Defaults — Click once to return the FBS to default settings.
Figure 32. Feedback Suppressor
DMP 64 • Software Control 41