You generally need special headphones for that and they really didn't work that well 20 years ago. I don't recall there being any way to tell the Half Life engine or my sound card "output 6 channels to the headphones" and the engine wouldn't do A3D if it was a stereo device.
By having a 5.1 setup surrounding me (about 2 feet away in each direction, it was.. cluttered), the brain produces a surround sound effect the way it does in normal life.
An expert would have to speak further about how headphones can emulate that, but I don't recall it ever really being a thing in the early 2000s.
You are the first person I’ve ever seen talk about how a surround sound speaker system is better for competitive shooters than stereo headphones, but I might be showing my age here since you are talking about the 2000’s :P
No, I played CS1.6 and I wouldn't consider playing without my headphones.
I didn't have a surround sound system because I was a teenager, but I knifed thousands of noobs coming around the corner wall in iceworld because they were too dumb to walk.
I'm guessing it was an identical effect to the surround sound, it was basically radar. You could hear people across nearly the whole iceworld map.
I have a vivid memory of playing Doom 2 on a 486 in the 90's, hiding in a building with a cyberdemon circling around the outside, and being able to tell exactly where he was based on sound alone. Needless to say Doom produced no more than 2 channels of audio.
Interestingly Doom's audio code was licensed from a third party. When they open sourced it, they had to rewrite that part; I think Carmack said he backported Quake's code. I wonder if that third-party code was just really good or something.
You had to tweak a lot of settings with EAX to make it sound decent, but you could also configure it so you could hear extreme distances, giving you quite the advantage. I bought a Sound Blaster Audigy Gamer card because of that. I had a huge config file that set all sorts of network settings, and even bound PgUp/Dn to cycle through various ex_interp values.. lol
By having a 5.1 setup surrounding me (about 2 feet away in each direction, it was.. cluttered), the brain produces a surround sound effect the way it does in normal life.
An expert would have to speak further about how headphones can emulate that, but I don't recall it ever really being a thing in the early 2000s.