There was a topic I just saw on floor monitors that made me remember I was going to ask this. At our gig Saturday we brought the PA mains and mixer, our friends band played before us and he decided to bring powered wedges (Carvins, but not sure how old as they've been in his uncles studio for years) Anyway, levels for the mains sound alright, but as soon as the monitors go on...BAM! feedback city...I tried my best but couldn't get rid of the feedback even at very low levels, so we played without them. Their guitarist claims that at his practice space he uses them pointed right at him with no problems. Also I noticed he was using a Sennheiser e835, same as our vocalist. At our practice space her mic constantly has feedback when standing in front of the monitors. I'm no pro sound guy, but I'm the only one who has bothered to try and learn it. So how can I get rid of the problem. Is it a gain problem? Are these mics just really hot? Or are their frequencies I need to know about and try to adjust? Thanks guys!! I really want to learn this stuff!