Note that the Vista DirectSound emulation sends mixed audio content to the standard OS audio path, and offers no "direct" path to hardware at all. Since the whole point of DirectSound acceleration is to allow hardware to process unmixed audio content, DirectSound cannot be accelerated in this audio model.
Game Audio Issues
This results in bugs such as loss of EAX functionality in games to complete incompatibility, depending on how the game title was authored and how well the Microsoft DirectSound emulation code works. In addition, given this model any and all bugs that are exclusive to DirectSound games could not possibly be due to Creative audio drivers or any other IHV (Independent Hardware Vendors) audio drivers.
Custom Audio Effect APOs
Vista does support insertion points for custom audio effects
(http://www.microsoft.com/whdc/device/audio/sysfx.mspx, http://www.microsoft.com/whdc/device/audio/vista_sysfx.mspx)
depicted above as APO1 and APO3. Forthcoming Creative audio products will use APOs to implement certain features, but these custom effects do not allow acceleration of DirectSound because as mentioned above they receive mixed content, not unmixed content.
Creative supported hardware acceleration for Gaming and Music Creation
The good news here is that, as depicted above, Vista still permits proprietary user mode to kernel mode driver stacks, which means that Creative products may continue to support non Microsoft driver models and technologies such as
OpenAL (http://www.openal.org) for 3D gaming,
SoundFont Management System (http://www.soundfont.com)
ASIO (http://www.steinberg.net) for audio content creation.
As was the case in Windows XP, these audio interfaces will continue to be thin pedal-to-the-metal APIs that allow user mode applications to access hardware features directly.
OpenAL - the key to optimum audio for gaming in Windows Vista
OpenAL continues to be the most widely used API for optimum 3D sound in PC gaming and the direct to hardware path offered by this API is the only way to access the hardware accelerated audio processing offered by cards in the Sound Blaster range.