XAudio2 is a lower-level audio API for Microsoft Windows, Xbox 360 and Windows Phone 8, the successor to DirectSound on Windows and a supplement to the original XAudio on the Xbox 360.
XAudio2 operates through the XAudio API on the Xbox 360, through DirectSound on Windows XP, and through the low-level audio mixer WASAPI on Windows Vista and higher.
The RTM release of the XAudio2 library is included in the March 2008 DirectX SDK, enabling a programmer with Visual Studio to use XAudio2 in a Windows, Xbox 360 and Windows Phone 8 project.
XAudio2 provides mixing and signal processing for high-level audio APIs such as XACT and as well provides the programmer with high-level functions related to spatial processing.
XAudio2 abstracts audio generation by separating sound data from "voice", allowing each voice to be filtered by programmable digital signal processing and effects processing functions. Voices can be "submixed" together into a single stream.
XAudio2 can natively decompress XMA on the Xbox 360, xWMA on Windows, and various ADPCM codecs on both platforms. XAudio2 2.8, the latest version supports Windows Store App development and can be used in C++/DirectX apps.