Yeah, something is definitely wrong when TV signals sound better than bluray, let alone a DVD. I've never tinkered with a PS3, but you are selecting the correct audio track on the bluray disc's menu? If DTSMA, often there isn't anything to choose, if it's TrueHD then more often than not you have to choose, and it's mch PCM you always have to choose from what I remember.
You also don't have any "downmix" engaged on the PS3 I imagine. Keep it disabled.
Also, please defeat DRC, or whatever the equivalent is on the PS3. Otherwise, IMO, some movies will sound awful, particularly those with TrueHD with terribly implemented autoflagged DRC, such as Iron Man.