Using preset 6 is indeed the simplest way to use the i7100. This sets every filter to automatic mode, which means one filter will seek feedback, and when it finds it the next filter will seek the feedback, and so forth.

Setting the threshold to a low level will allow the i7100 to detect and kill the feedback earlier. There's really no one threshold setting you can use. Itll all depend on the acoustics and set up of your system, as well as how loud the system is and how close your microphones are to the speakers.

If you try it at -50 dB then slowly increase the threshold while testing it until you find a setting that kills feedback while still allowing you to maintain fantastic audio quality. So something like this should get you going: turn the Function jog-wheel until the Preset LED is lit up, then push the jog wheel in. After this, turn the wheel and select preset 6 (by pushing the jog wheel in). Then use the function wheel to select a new Threshold (turn the jog wheel, highlight the Threshold LED, and push the jog wheel in - you can then select the threshold).