On the other hand, I will say this about Cowboys Stadium.
1. The loudest parts of a football stadium are generally the endzones because there's crowd noise coming from three-sides. Many of these stadiums reserve the end-zone seating to the boisterous fans. For Cowboys Stadium, the endzones are lined with the luxury suites and the end zone seats located above - where the cheerleaders line up. Of course, these luxury suites don't seat fans as densely as regular seats and generally have quieter fans.
2. That stadium is humongous. I don't know the stats or science of acoustics, but possibly it's loud in the stands, but that crowd noise doesn't get to the field. Arrowhead Stadium is intimate -- the distance between 50yard seating on one side to the other side is much, much closer than it is at Cowboys Stadium.
3. I do remember an article several years back discussing the architecture of Cowboys Stadium. Essentially, Jerry Jones decided to make the acoustics of the stadium 50/50 to accommodate sporting events and concerts. For crowd noise with sporting events, you want echo. However, echo is horrible for concerts. As a result, Jerry Jones went down the middle whereas Seahawks Stadium is great for crowd noise - but horrible for concerts.
4. The Huge End Zone Glass Doors - glass doesn't contain noise as well as steel.
