I don't think the accoustics of the stadium had much to do with how low the vocals were in the mix. I've only seen Tool once before, at Coachella last year, and was a little suprised that Maynard never left the drum riser or spoke much. I didn't really think the quiet vocals were that noticable, the rest sound of the music sounded great. The crowd was pretty dead, I was suprised to be standing that close to the stage without seeing any kind of moshing.

Man, the line for beer was awful. They need to just hand you a plastic bottle or can, that waiting for each and ever single beer to be poured for the line in front of you sucks.