Leeneia's point about not having the sound too loud - it looks to me as if you'll need to put some more speakers in around a third of the way down the room (preferably on a delay line), as most of the sound will be absorbed by the carpeting, audience and false ceiling.

Okay, on the face of it that seems a contradiction in terms - more speakers = louder... No! In the trade we call it 'low level distribution' - instead of blasting out the first few rows so that the people at the back can hear, you spread the sound out and keep the overall level down...

Why the delay line? Simply, people sitting further back would hear the speakers near to them, then the front speakers a few milliseconds later (think seeing a cricket bat hit the ball, then you hear it). So you delay the sound so that they hear them both simultaneously.

Well, you did ask!

Seriously, see if your sound man is up to the job, and take professional advice if necessary.