Originally posted by: Bovinicus
HL's sound engine is good enough that you should be able to hear positional audio without either A3D or EAX enabled. In my opinion, the game doesn't work well with it. Or, maybe my sound card just doesn't like it either, but I have a Philips AE. In other games, EAX2 and A3D sound excellent, even EAX sounds okay. A3D is leaps aound bounds ahead of EAX, but I prefer EAX2 over A3D.