Reddit mentions of Disquisitio De Herodoti Philosophia... (Latin Edition)

Try this.

If one particular freq is feeding back, let's say 400hz, bring down 400hz on the EQ but don't bring it too far down. After bringing down 400hz, contour the surrounding freqs, 315hz and 500hz, by bringing down those freqs but not as much as 400hz. This [pic] (http://www.audiocity2u.com/images/catalog_images/1270877631.jpg) is a good example of what I'm talking about.

And you're probably correct about the down firing speakers that are in your gym causing the feedback but you're probably also correct about the acoustics of the gym causing the muddiness in the sound. But it seems that the PA system that you brought would be a better solution than the House speakers. So try this if you aren't already. Place the speakers forward of the performers. So what I mean is, if the performers perform on a stage, place the speakers so they're at least parallel with the front of the stage and not behind it. Or if there isn't a stage, place the speakers so that they firing in front of the performers. You don't want a situation where the speakers are placed behind the performers. This makes it difficult to notch out the freqs that are giving you problems.

It's too bad that you don't use Shure Lavs because I highly recommend these [Pyle Pro headsets.] (http://www.amazon.com/Pyle-Pro-PMEMS10-Omni-Directional-Microphone-System/dp/B003D2YRLA/ref=sr_1_3?ie=UTF8&qid=1448984220&sr=8-3&keywords=pyle+pro+headset) Even though these Pyles would seem like they would suck, they actually don't. I own 4 of these and I've successfully used all 4 at once and feedback wasn't that much of an issue and they sounded great. I've heard, although I can't verify, that Audio Technica will attach a 4 pin Hirose connector that they use on any mic for $30 bucks. It might be worth a shot since 3 of those Pyles with the connector conversion would be around the same price as 1 of those Audio Technicas.