You want 4.0? Four channels is usually more of a PITA than five or seven. Some games don't even have a setting for four. When I had a quadrophonic setup I used to let the computer send a 5.1 channel signal to my receiver, which would matrix the centre channel into the two fronts. This wasn't optimal, but some games just refused to put out a four channel signal without loosing a part of the soundstage.
No, I mean:
If they can get the proper stereo translation from an in-game character, with a fire burning to his left and a bomb going off to the front, to 2 speakers...
Why can't they do the same thing, with 4/5/7 speakers?
Fire to the left, bomb going off to the front, footsteps behind?
....
No, better idea:
Man standing in a warzone.
Guns blazing to the front. Building burning to the left. Footsteps to the rear.
2 Speakers:
The only thing distinguishable is the fire. The Gunfight and the guy sneaking up on you just sound like they're coming from between 2 the speakers.
Physical limitation, yeah?
4/5/7 Speakers:
What should happen is that all things should be distinct. The gunfight should be coming from in front of you, the fire should be on the left as with the plain stereo system, and the footsteps should be definitely behind you.
Not a physical limitation, you have all of the speakers in the right places.
The problem is in the program, right?
The problem is with the in-game character, right?
What I don't get is why this problem exists. Surely if you can reproduce the sound from 2 directions: side to side, surely you can reproduce them from four directions? Side to side AND Front and back?