I may step on toes here. At least, have a lot that disagree with me.
Crowd noise, in my opinion, doesn't have any relevance on the game with the exceptions of a few plays during the game. In those situations, the crowd responds.
What am I saying?
I think it is over-rated.
I can think of a lot of teams that have won, and won big, with crowds that aren't loud; subdued in fact.
Can it make a difference in a game? Sure, but not as often as most seem to think.