To be fair, it's some pretty intense clapping. I imagine if the team's playing well than it probably is quite lively. Though you'd hope it would be with 50,000 people in.
The atmosphere at St James' Park is like watching a pathe news real of a match - total silence occasionally interspersed with a burst of clapping when one of their players does something well (i.e. about 5 times a game).
I'm pretty sure you could retrofit some acoustic panelling or false ceilings or whatever to do pretty much anything you want with the acoustics. Whether it would be in any way affordable is another matter entirely of course.
I think we need to incentivise people more.
The first person to stop singing after kick-off, will be shot.
The second person to stop singing, will be shot twice.
And so on and so forth.