Any home/corp. AV professionals here? Pub meeting room PA question

I wasn't quite sure where to put this but I thought I would try here since this forum is full of smart and talented people.

I am an IT guy but have been tasked with setting up audio in a public meeting room approx 40'X 100. There are speakers mounted into the ceiling throughout the room that are amplified and have XLR connections into the house system. I have a 16 channel sound board with XLR microphones into it. It works ok for speaking during meetings but if the volume is turned up then I get terrible feedback. Most of the mics are live and do not have an off switch on them so I suspect that is part of the problem. Anyone have any ideas how to improve this and stop the feedback? I am an I.T. pro and not an AV tech so any help appreciated. Thanks


EDIT: The system just needs tuned or an audio pro to do it so I guess I am asking if there is an cheaper or simpler way to maybe do this myself.

 

@ToyoMafia

 

I’m willing to have a phone call about this. I’m on a show today. Send me a PM with your contact