Here's a quick video I made with my Allen & Heath CQ-18T showing how you can use the Feedback Assistant to eliminate feedback from your monitors and main PA.
Each box on the left represents one of the 16 total filters.
Blue – Fixed mode filters.
Green – Live mode filters.
Orange – Currently selected filter.
Touch a box or a point on the graph to select a filter for adjustment.
Adjust Filter – Make width and cut adjustments to the selected filter. Select ‘Reset’ to remove the filter and make it available for use by the detector.
All Filters – Adjust width and cut for all active filters at once.
To reset all filters, use the reset option from the dropdown menu at the top right of the screen.
Filter Modes
Fixed filters remain in place until they are manually deleted, the FBA is completely reset, or if the Feedback Assistant ‘steals’ them. Up to 12 of the 16 filters can be in Fixed mode, always leaving 4 for use in Live mode.
Live filters recover over time and once fully recovered, will switch back to being unused filters. They can be deleted individually or with a complete FBA reset. All of the 16 filters can be used in Live mode.
Automatic re-use of filters
When all filters are already in use, but a new feedback frequency is detected, the Feedback Assistant can re-use or ‘steal’ an existing filter, using logic to decide the best possible outcome i.e. the least amount of feedback.
Note that Live mode filters can only steal other filters already in live mode and Fixed mode filters can steal any filters.
On power up
Every time the CQ is booted, all Feedback Assistant instances are set to a ‘pre- show’ state. Fixed filters, the Live Recovery setting, ‘All Filters’ settings and In/Out state are remembered from last power down. Any Live filters will have been removed. Detect Hold is active. Mode is set to ‘Fixed’.
Copy/Paste
Copying and pasting includes all filters and settings (e.g. Live Recovery). This means that when pasting to another output (or back to the same output), the state of the FBA will be exactly the same.
Store/Recall
When using the FBA Library, Live filters are not stored or recalled. All Fixed filters, the Live Recovery setting, ‘All Filters’ settings and the In/Out state are stored and can be recalled.
Scene changes
Scene changes do not affect the Feedback Assistant settings directly, but they will usually change levels and processing which might affect which frequencies are more likely to feed back.