Honestly, you can never have enough volume for a football game. The louder, the better.
I love leaving games with my ears ringing, both from the crowd noise AND the loud speakers. I want noise, I want volume, I want craziness, I want mayhem, I want freakin loud music, and I want it louder!!!!
...this coming from a guy who has already lost some hearing because I love lots of volume.
For people who think its too loud, bring in those little foam ear plugs. But, if its too quiet, there's nothing you can do. Always error on the side of "too loud" for a football game, never the opposite. It takes away from the atmosphere.