OpenAl Software allows the rendering of multi-channel three-dimensional positional audio because it is a cross-platform audio API. The style of its API plus the APIs conventions have been deliberately designed so that they resemble OpenGL. It started life in the year 2000 and has been used by NVIDIA nForce Creative Technology and Apple.
A Clever piece of Audio Software
The current versions of OpenAl are proprietary but previous versions were open source. Instead of using proprietary systems like A3D and EAX you may use OpenAl instead. It is a 3D audio library that was created to replace 3D audio systems like A3D and EAX. It is an advanced piece of software that is very good at manipulating sound especially when used with 3D audio systems. The current software is proprietary but you can get the open source version known as their 'Soft' version if you wish to tinker with the code yourself.
Conclusion - An Amazing Piece Of Software
One of the fun features about OpenAl is that it is able to add sound degradation. For example if you are playing a game it may simulate attenuation where it appears as if a sound is degrading over a certain distance. The software is also able to create a certain amount of realism by employing the Doppler Effect where the frequency of a sound changes because of motion and/or because of material densities.