Many of us have heard the virtually unintelligible audio that sometimes comes from an announcer trying to shout into a mic to overcome a super noisey environment. I'd like to try to fix that for our high school pep rallies.

Typically the kid doing the announcing is about 30 feet out in front of the floor-level loudspeakers with a hand held, hard wired mic feeding a mixer, which feeds the amp. I don't know the make or model of the mic yet, but I intend to find out.

I guess the main contributing possibilities are feedback of ambient noise, and overloading of the mic. I assume that the guys at the mixer have done the best they can with levels. They've been doing this for a while. I've measured the average level of ambient noise in the room at 80-95 dB. But it seems to me that with the right mic choice and technique we should be able to get enough of a differential between ambient noise and the annoucer's voice to achieve reasonably clear audio. Am I wrong?

Thanks in advance for any recommendations.

There's only so much one could do, but to get as much going in your favour as possible my first thought would be to insure they're not using an omni mic.

The revrb time (RT60) in most gyms is too long for good intelligibility. Some things that help are:
Wall and ceiling treatment (to lower the reverb time)
Very directional speakers (sound only hits audience)
Move person speaking behind the loudspeakers (also improves gain before feedback)

Sam