How Virtual Surround Sound Works
Virtual Surround Sound (VSS) simulates true, multispeaker surround sound by processing 5.1 audio into two channels (left and right). The spatial algorithms in VSS systems are sometimes used to bounce signals off walls to approximate the effects of speakers to the sides and rear.

Pros: More compact, easier to install and usually less expensive than 5.1 systems, with far less speaker-wire clutter.
Cons: The absence of rear speakers and a subwoofer means less rumble in movie explosions (and less bottom on your CDs) and a smaller sweet spot where audio effects are most dramatic.