Footsteps aren't playing. Also, the playback position isn't accurate.

 I can have a tank up on my from behind and I don't hear it. I sometimes don't hear my own defibs. I sometimes don't hear my own gun shots. I don't hear my squad mates firing right next to me. Seems like there is a limited number of sounds at any given time and once that limit is hit, no more sounds.

Every once and awhile I get into a match and I can hear everything, it's amazing. I've heard people running up on me and could react intime to get a kill. Amazing!