I've definitely heard louder games on tv. Last years NFC championship, '09 nfc championship. Eagles/rams last year. I've also heard some cheers for the 49ers from the crowd. You were there so of course it seemed loud to you, that's not what I heard from my chair that was the closest seat to the tv.
So you are judging crowd noise from your couch? That's funny. The same exact crowd noise can sound differently on different broadcasts depending on the filters used by the networks. If you want real crowd noise, get off the couch and to the Dome.