Creative has extended the support for their OpenAL wrapper, dubbed ALchemy, to include functioning with their Audigy series of cards. ALchemy allows software products that utilize EAX to operate under Vista without compromises in features or quality.
“In Windows Vista, Microsoft has decided to remove the Hardware Abstraction Layer (HAL) for DirectSound and DirectSound3D. The HAL is the software layer that in previous Windows operating systems enabled an audio accelerator such as the Sound Blaster X-Fi to provide DirectSound3D applications with hardware accelerated audio. This enabled soundcards to perform tasks such as sample-rate conversion, mixing, 3D spatialization using HRTFs, filtering, and effects processing. Without the HAL, DirectSound on Windows Vista will be rendered in software with no advanced functionality such as EAX.
The audio changes in Windows Vista do not affect OpenAL however. For audio cards that feature 'native' OpenAL support, such as the SB X-Fi series of cards, there is no need to worry! Games that enable support for OpenAL will continue to run just as they do on Windows XP - with hardware accelerated audio and effects. A listing of OpenAL titles can be found at http://www.openal.org/titles.html.”