Behringer FBQ2496 Feedback Destroyer

The FBQ2496 is the fastest (>0.2 sec.) and the only 96 kHz Feedback Suppressor on the market. Using an ultra-fast feedback detection algorithm, it automatically and 'intelligently' locates up to 20 feedback frequencies per channel and sets extremely narrow notch filters to 'destroy' them, leaving the remainder of the signal virtually untouched. Easy does it: with the 'Set-and-Forget' default setting plus the Panic button, your FEEDBACK DESTROYER can be up and running in no time! The auto mode continuously monitors the mix, resetting programmed filters automatically, while the manual mode allows individual setting of up to 40 fully parametric filters with frequency, bandwidth and gain adjustment. Open MIDI architecture means that future software updates and flexible communication with digital equipment are a no-brainer. With its various modes you can master just about any live sound situation or use it as a creative sound-shaping tool.

Help with using the FBQ2496
From new the unit comes with the internal filters (of which there are 20) all set to parametric. You have to manually allocate these filters according to your application, either single shot, automatic, or parametric. Since the default is 20 parametric, this leaves NONE for the LEARN Mode which the unit needs to operate as a feedback destroyer automatically. To adjust this, hold down the PEQ button for a few seconds, the display will show 20 - twist the control knob and set this to a lower number such as 10, or even to 0 if you want all 20 filters to be automatic. If you have set 0 filters to PEQ mode, all 20 will be free for Learn Mode. Press PEQ again to exit PEQ mode. Now press Learn Mode, the display should read 5 0, twist the knob until it reads 5 20, then there will be 20 filters allocated for LEARN MODE.