The Audio Driver module which sits on top of a particular Audio module abstracts away the underlying APIs (of FMOD etc) to give you use of the standard commands.
You can of course directly use the Audio module if you want/need to, which gives access to all that audio-library's functionality, like better control over effects, 3D, etc.
As for a comparison :
http://www.fmod.org/index.php/products/fmodex
http://www.un4seen.com/bass.html
http://www.ambiera.com/irrklang/features.html
They are all cross-platform, except that BASS is not available on Linux.
Essentially, they all accomplish the same thing, in slightly different ways. Some have more features when it comes to adding effects.
It depends what you need out of your speakers :-)
You can of course directly use the Audio module if you want/need to, which gives access to all that audio-library's functionality, like better control over effects, 3D, etc.
As for a comparison :
http://www.fmod.org/index.php/products/fmodex
http://www.un4seen.com/bass.html
http://www.ambiera.com/irrklang/features.html
They are all cross-platform, except that BASS is not available on Linux.
Essentially, they all accomplish the same thing, in slightly different ways. Some have more features when it comes to adding effects.
It depends what you need out of your speakers :-)