help

It's not too loud. It's the red lines that appear on the left and bottom sides of your mini map that is your alert. The alarm is more visual than audio. It confused me too. This ability isn't the greatest.

Yeah, same here. I have it in my set up but nothing shows up on screen or is mentioned when an enemy gets close. Who knows...I am sure they are working on the bugs...at least we hope so.

It could be once you upgrade it, that's when you hear the beebing sound. If not, its a sound glitch or crytek removed it.
The demo didn't have it either. But the 360 demo did. They also removed the power melee and for some reason I can't pull off a stealth kill. I can thank the community of complainers for this change. Now every close encounter is a boxing match.

the stealth kills do still work, i've done it and had it done to me.

I haven't tried it in multiplayer but in single player it is a slightly obnoxious beeping sound. It starts beeping faster as you get closer to a hostile and slows down as they get farther away. It didn't help me much so I wound up dropping it for a more useful enhancement.

It doesn't start beeping until you get to level 2 of perk. It's still not that loud though. I'm 110 away from level 3 of perk. I hope it will be louder.