Thank you all for the responses. I'll try to answer your questions as best possible. Right now we're in the very beginning stages. The arena is probably 1-2 years out from being done at least. I'm just trying to get a general idea of what to look for with an arena system that will provide enough volume and low frequency for things like pep rallys and other loud events. We will be hiring a company so we'll be looking at proposals from different vendors in the near future. The problem we've had in the past is that we've paid vendors good money (I think someone said $50k) for a gym system that can't provide enough volume for these events. I don't know the budget is so far but I want to push for getting a better sound system rather than spending less and having regrets. Also i think part of the problem is when they were planning for the gym system, they didn't fully communicate what events would be happening there and what their expectations were for the sound system, so they came up with a decent but still underperforming system. Just hoping to avoid that. Thank you all.
You definitely hire a system consultant to work with you on the design.
Try first with your project's architect, it may already be part of the scope and if you don't do anything you will probably already have a "cookie-cutter" system as part of the plan package.
Intercept that process now and either work with the architect's audio consultant or hire your own. It's best to have all 3 of the entities together for the design process -architect, consultant and client end-user.
Interview and study your consultants portfolios before contracting with them, a good one is what makes the difference between an underperforming system and project success.
Once the design and plans are set you can then go out for bids from reputable audio install companies.
Don't let the general electrical contractor get it, they will screw it up (sorry internet readers, find me just one example of this resulting in success and I will recant my opinion)
This also results in a system that's tightly integrated into the building with the cost rolled into the whole project, (making it a bit more palatable)