The Proximity Alarm for the PS3 does not appear to be working...I have maxed it all the way to level 3 and I still have not heard or seen anything that resembles a warning when an enemy is nearby....I even turned the music all the way down to ensure I was not missing a noise due to that. Anyone know how this works or if there is a problem and a patch is in order? Thank you.

I saw a few posts about this and I never even knew there was audio to it before I read about it. Anyway once I upgraded it once, I can now hear the audio. You should see two red bars that expand around your minimap when an enemy approaches. The sound varies with proximity. Barely close and you should hear just a little beeping. If they're right next to you, you should hear a prong like sound that's very prominent.

I couldn't hear anything at level 1 but at level 2 I do hear a beeping sound.