I seem to be getting different answeres and don't know which to trust. It definately won't be the chick at best buy.
As Celtic_D says it decodes Dolby Digital sound. This is usually for a surround sound system, they also have Dolby Pro-Logic which to my understanding delivers the sound as if it were encoded as a Dolby Digital product even if it isn't so. THX Sound does the same thing except I don't think they have a pro-logic style deal. I've only had a chance to hear the Dolby version firsthand but I do notice a difference between those with decoder and those without (certain sounds are more expressed and refined), however I hear THX is the best.
