Originally developed by Loki Software in 2000, Open Audio Library, more commonly known as OpenAL, is an audio API and available for multiple operating systems. OpenAL is used for rendering multi-channel 3D positional audio. The style of OpenAL's API is very similar to that of OpenGL.
OpenAL was also designed to replace other proprietary 3D audio systems, like EAX and A3D. It is also capable of simulating attenuation, the Doppler effect, and material densities; adding realism to video games.
Note: Although OpenAL has the word "Open," its name it is not open source.