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Assigning DFR
Two DFR blocks are assignable to any channel input or mix output. When using two or
less microphones, assign the DFR to those channels to prevent feedback from routing to
the mix bus. Additionally, if a microphone is designated for a chairperson or host, DFR
should be applied to that channel to ensure that remains stable and does not feed back.
Apply DFR to a mix bus when using multiple non-stationary microphones or when
trouble frequencies are feeding back simultaneously in multiple microphone channels.
Filter Types
By default, the DFR processor filters are unlocked to dynamically adjust as feedback
frequencies are detected. However, you can specify how many of the total number of
notch filters will remain fixed (locked). Use a greater number of locked (fixed) filters
on input channels for stationary microphones. In this instance, the room acoustics
define the dominant feedback frequencies, which do not change appreciably. Use a
greater number of the dynamic (unlocked) filters on input channels for wireless or hand-
held microphones. In this situation, feedback frequencies change drastically as the
microphone user wanders the room or sound stage.
Both fixed and dynamic filters will automatically deepen as additional feedback is
detected.
• Locked (Fixed): Once set, the frequency of a fixed filter will not change until it has
been cleared or a new frequency manually entered.
• Unlocked (Dynamic): Frequencies are automatically assigned by the DFR as
feedback is detected. Once a filter is deployed, it remains at that frequency until all
filters are used. At that time, the DFR redeploys each dynamic filter at the newly
detected frequency, in the order of oldest dynamic filter to newest.
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⑥ ⑦
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Filter Width
The DFR offers two width options for notch filters. By default, filters in the DFR are
deployed as High Q filters. As a high Q filter gets deeper its Q increases up to 101
(1/70th of an octave). You can also set filters to deploy at Low Q. Low Q filters affect a
slightly wider range of frequencies by maintaining a Q of 58 (1/40th of an octave) as they
deepen. To change the setting for an existing filter, select the Q-Width drop-down menu
in the filter row.
New Filter Q: This setting determines the Q width for new Unlocked (Dynamic)
frequencies as deployed by DFR.
