As such, they've made major improvements to the audio portions of DirectX 8. The sound APIs are still referred to as DirectSound and DirectMusic, but there's not a really big distinction between the two anymore. DirectMusic is now powerful and robust enough to handle not only interactive music but time-sensitive sound effects as well, and Microsoft suspects that developers will actually use the DirectMusic interface for most game audio. Developers can assign arbitrary sound looping points, submix channels before sending them off to DirectSound for playback, apply filters independently to each voice, and stream sound playback automatically. Music tracks can play back as 3D sounds, so you can have a DirectMusic track playing through a radio on a desk in a 3D game, and it will be represented as a 3D sound.
Designers can more accurately control the sound in a game through the use of scripts, too.
A game event might call upon a sound script instead of controlling multiple sound events directly. This should make it easier for the sound specialists to control the sound in games without so much work from the programmers. When developers create games to be played over the Internet they might use DirectX, but usually not its networking functions, called DirectPlay. Most developers have been unhappy with its performance and features and have opted to use their own. Microsoft has a vested interest in making Internet gaming easier to accomplish for developers and more popular among gamers, so they've really overhauled DirectPlay.