I think the concert hall sound fields that A/V receivers provide could have a truly realistic feeling if it made use of surround sound to include:

- coughs both open and closed mouthed
- weight shifting in seats with various squeaking sounds
- dropping program books

The above are already present in some recordings but how much more immersive it would be if true HD audio processed these!

There could be a setting to include some extreme options:

- murmurs from old ladies
- slowly unwrapping cough drops
- lone applause in silent parts