Extron electronics DMP 64, User Manual

Page: 31 / 152

Feedback Suppressor
The Feedback Suppressor (FBS) is used when there is indication of feedback in live
situations. Dynamic filters automatically detect feedback on a live microphone channel,
and engage a set of up to five fixed and 15 dynamic filters to counteract the frequency
peaks at the detected feedback frequency. Up to 15 separate filters may be employed at
any time. The 15 filters act in a FIFO, or first in, first out rotation. If all 15 filters are being
employed, when an additional feedback frequency is detected it will overwrite 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 3 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 for dynamic
filters:
• Clear All —
clears all dynamic filter settings.
• Lock — locks the dynamic filters to 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.
Figure 21.
Feedback Suppressor
DMP 64 • Operation 25