Do you like Gray ?

[WindexGlow]

HuntFOV = "270"
HuntSpeed = "3.5"
HuntForLostPlayerTime = "6.0"
HuntMinSeeChance = "0.2"
HuntMinHearVolume = "0.2"
HuntSound = "infected_hunting"
HuntSoundMinInteraval = "5"
HuntSoundMaxInteraval = "10"


Doesn't look for you too long; increasing the number will probably make things..more interesting ;-)
C:\Penumbra\Penumbra Black Plague Demo\redist\models\characters\character_infected\character_infected.ent
(I put my installation in a special folder; yours will be located in a different spot, probably in paradox\penumbra black plague demo

Have fun.