http://www.cmedia.com.tw/news_xear3d_ex.html
http://www.cmedia.com.tw/pci_audio_new.html - compatibility list.

Missed this when it happened. If you have a C-Media card (see above) in vista - update your drivers and get your DirectSound3D/EAX back.

I assume it's very similar to DS3D-GX on the Xonar.