- Range: 20 feet
- Requires Line of Sight? No
- Requires Line of Effect? Yes
- Usable for Combat Targeting? Perception check at -10 to detect the square a creature is in. Detected creatures have total concealment (50% miss chance)
- Bonus/Penalty vs. Stealth? Perception check at -10 to detect the square a creature is in. Detected creatures have total concealment (50% miss chance)
- Ignores Invisibility? Yes
Description: Audio senses allow creatures to sense the presence of creatures, but are generally poor at providing enough information to target a creature in combat. A creature with standard hearing can make a perception roll to notice the existence of another creature within 20 feet, assuming they have line of effect to the creature. The perception roll has a DC equal to 10 unless the creature has entered a stealth stance, in which case, the DC is the result of the creature's stealth roll. Invisibility grants no benefits to a stealthed creature against a hearing perception check.
A creature with standard hearing who beats the perception DC by 10 or more also learns which square the target is in, though the creature still has total concealment if no other sense (such as vision) is available to target them. Standard hearing can never provide a result better than this -- you know what square the creature is in, but the creature has total concealment. You must always have line of effect to use hearing, though some barriers, such as doors, may allow hearing checks at a greater penalty to the standard DC (depending on how solid the door is).
If the environment that a creature is trying to listen in is noisy, the DC for the perception check is increased by anywhere from 2 to 20, depending on how cacophonous the additional noises are. Generally, trying to discern one target among several when none are attempting to be quiet is a -2 penalty for each additional target (though there is no penalty if you don't care which target you find).
The sounds of battle typically inflict a penalty of -10 if listening for a single target amidst the battle, but only -4 if you only wish to locate 'any enemy creature'.