EAX is a library of extensions to Microsoft's DirectSound3D, itself an extension to DirectSound introduced with DirectX 3 in 1996 with the intention to standardize 3D audio for Microsoft Windows, adding environmental audio presets to DS3D's audio positioning. Ergo, the aim of EAX has nothing to do with 3D audio positioning, this is usually done by a sound library like DirectSound3D or OpenAL. Rather, EAX can be seen as a library of sound effects written and compiled to be executed on a DSP instead of the CPU, often called "hardware-accelerated".