The loudest game I've ever heard was the Philly playoff game in '06 (or '07) in the dome.
This game was lounder than the re-opening imo. I remember taking the escalators up to the terrace and we couldn't believe the noise level in the concourses. Mind you, this was 30 min before kickoff and people were just going to their seats. I looked at my buds and asked them if they'd ever heard what we were hearing at that point, and none of us had. It was special loud. It only got louder from there.