What's a game without audio? Dull comes to mind. Given the improved speaker systems now available, it's not surprising that theater-quality audio is a requirement for high-performance gaming.
To meet the more demanding gaming requirements, there's been quite a dramatic increase in sound-generation process complexity. It's no longer sufficient to provide sophisticated sounds. Now, they must be positionally correct for the listener with respect to the game. When a monster drags a body down a corridor located behind and to the right of the player, the monster should sound as if it's really behind the player.
In some ways, audio processing is more complex than the video, since sounds may come from areas that aren't in view. Video processing can reduce some of the complexity by narrowing the focus to what is viewable.
On the other hand, hearing is less discerning than vision. The number of audio sources also typically is lower than the number of objects in a video environment. Therefore, computational complexity is lower. Audio gaming support is likely to see more improvement at less cost over the next few years.
