OpenAL.

The OpenAL Installer for Windows will install the OpenAL 1.1 libraries,
enabling support for core OpenAL operations as well as extensions such as EAX
and EFX. The installer supports both 32-bit and 64-bit versions of Windows.

DLL Version numbers:

• OpenAL32.dll version 6.14.357.22
• wrap_oal.dll version 2.1.8.1

Changes and Bugfixes

• Added new enumeration extension (ALC_ENUMERATE_ALL_EXT) to use AL on any
  soundcard / audio endpoint
• "Generic Hardware" device only appears in the enumeration string if it can
  be used
• Fixed alcGetIntegerv's requirement for an active context
• Fixed alcCaptureOpenDevice so that it returns 'NULL' if the capture device
  fails to open
• Fixed software reverb bugs (Reflection Delay and Air Absorption
  HF)

Download from here
DirectLink
http://connect.creativelabs.com/openal/Downloads/OpenAL11CoreSDK.zip