there have been plenty of versions of 2 speaker directional sound, the most prominent being QSound. So how does it work? Easy. You only have two ears and they detect sound the same whether it's from a speaker or someone standing behind you. It is all about sound pressure and how BOTH ears perceive the rpessure. this is why people who are fully deaf in one or both ears don't have much equilibrium.
so anyway, the sound is encoded in such a way that it emits from the speaker a similar sound pressure as to what would happen if the sound came from x point in the room. the catch is that the sound is based from the pair of speakers, not from the user. also, room acoustics play ENTIRELY into the emulation. so if your room isn't acoustically perfect (for what qsound or similar requires) or you aren't standing perfectly in the middle and at such and such a distance from the speakers, the effect could be ruined.
this is why qsound actually worked nicely on arcade games. because the player was always guaranteed to be standing in the exact perfect spot.
