The best advice is to not panic when you get feedback. It isn’t a question of IF it is going to happen, but rather WHEN it is going to happen. Even the best audio engineers will experience feedback. You just have to be ready for it and have a game plan on how to handle the situation.
First, you have to understand how feedback occurs and determine which speaker(s) it is coming from. I realize this is basic, but it certainly can help narrow down where the feedback is coming from. If it is feeding back in a monitor wedge, then the obvious place to start is with microphones immediately around it.
If it is feeding back in the mains, then it can be a little harder to track down. If you are unsure about which channel is feeding back, then first place I would look is on the channel meters. Which ever channel is the source of feedback will show a signal and it will rise as the feedback increases. Again, the source is usually (but not always) an open microphone. If you have any condenser mics, that is a good place to start because they are more sensitive when turned up. Also, if you are in a more permanent setup, you have to think about what recently changed that might cause the feedback. In our church for example, feedback is rare. If we have a new musician/instrument one week and we experience feedback, I’m going to start with their setup because it is the one thing that changed.
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