We never lacked an atmosphere, even at the Olimpico. Nothing has changed but the stadium, which magnifies the effect.
It was clearly louder. You could see fans in the east and west fans involving themselves, so the curva would have been rocking.
I find it depends on the channel. Some broadcasts damper the crowd noise, whereas others it's much easier to hear.
It works both ways though. Sometimes they can mislead you, to add to the effect of the game. The prem is a good example. Man Utd, Arsenal, and host of other clubs are notorious for the "prawn sandwich" munching brigade, yet you can clearly make out the chants on TV, even though first hand accounts suggest otherwise.