I was wondering what anyones expierience with notch filters are. I would like to control feedback, but am not a techie. How easy is it to find the offending freq, and is it usually the same freq, or does it change from room to room? My thoughts; turn up the amp to the point where it starts to feedback, then twist the notch filter until the feedback is subdued. But wouldn't that make those notes softer than the rest? How much more gain can I realistically expect?