It's fine as is. It's great that the fans can have an impact on the game. You're stadium too quiet? Here's an idea, go to a game and cheer your ass off. It'll help.
The Seahawks are a different issue. It is by far the loudest stadium I've ever been too, and I've been to hundreds of NFL games over the years. Seen fans of all types, but the Seattle fans are actually rather tame.
They are the noisiest in the NFL, you say? b******t. I was at the MNF game against the Saints. I walked all over the stadium and stood and various locations. My observations:
1) There are plenty of fans cheering, but the individuals cheering as you walk by them are not noticably louder than many teams fans.
2) It's not a very hostile envirnoment. I was wearing niner gear head to toe and maybe caught a half dozen cutsie comments along the lines of "You're at the wrong game". Nothing remotely threatening. So, you feel pretty comfortable going to a Seahawks game as an opposting theam fans. Therefore, there are plenty of opposing teams fans at their games (far more than at niner games) and they do not make noice when their offense is operating.
3) There is an insane level of noise than emantes from under the covered sections.
4) The people in that section do not appear any more rabid that the rest of the folks in the stadium (in fact the endzone appears to have the craziest and loudest fans)
5) It's a specific noice that emanates from these covered areas, kind of like a long "ooooooooohhhhh" sound
6) As the opposing team huddles, breaks the huddle and the qb goes through pre snap reads, this "ooohhh" sound consistently gets louder. This happens even though the people that were cheering were already cheering. They are not noiticably or magically louder
7) The consistentcy of the lounder "ooohhh" sound is unreal, some would say inhuman....
8) A multiplicity of speakers line the inside of both overhangs pointed back at the crowd, such that if say you pumped that sound through the speakers, gently turning up the volume as the play clock winds down the sound would bounce off the crowd and towards the field, thus explaining the the covered portion of the field generates the vast majority of the noise.
My conclusion: The Seahawks, without a doubt, in my opinion, pump in crowd noise through those speakers.