Cross-platform Audio Creation Tool (XACT) is an audio programming library and engine released by Microsoft as part of the DirectX SDK. It is a high-level audio library for authoring/playing audio that is written to use Xaudio on the Xbox, DirectSound on Windows XP, and the new audio stack on Windows Vista and Windows 7. Xaudio is an Xbox-only API designed for optimal digital signal processing. XACT also includes X3DAudio, a spatialization helper library available on both platforms, Windows and the Xbox. XACT was originally developed for Xbox development, and was later modified to work for Microsoft Windows development as well.
The original release of XACT was in 2002 and shipped as part of the Xbox SDK only and was originally called the "Xbox Audio Creation Tool." It was designed to allow sound designers and composers for the original Xbox console to have access and control of the powerful MCPx audio chip in the console, which previously could only be accessed through program code, via Xbox extensions to DirectSound. XACT was the first widely available game audio tool that allowed a sound designer to run a tool connected to a running game and modify the sounds in real time, as the game was running, and support easy streaming of audio data from the console hard drive.
Later, under the XNA initiative, it was re-written to work on both Windows and Xbox and renamed the "Cross-platform Audio Creation Tool and included as part of the DirectX SDK.
Support for XACT has been carried over from DirectX to XNA. The XACT Audio Authoring Tool is also available in XNA Game Studio. With the release of Windows SDK for Windows 8 Developer Preview, XACT is no longer supported on Windows.
The XACT Audio Authoring Tool is a companion application used to organize audio assets into wave banks (single files containing multiple WAV files) and sound banks (single files containing instructions for playing the WAV files in wave banks). The wave banks and sound banks for a project are subsequently called by XACT from within the application.