Asus Xonar Essence ST - Manual (Page 50)

43 ASUS Xonar Essence ST
When I selected “Digital Output device” as the default audio playback device
on Windows ® Vista, the sound effects and UI controls do not work.
For Xonar sound cards on Windows ® Vista, there are usually two audio devices:
Speakers and Digital Out Device such as S/PDIF.
Speakers is the default device. Use this device to fully control the sound effects on
the Xonar Audio Center, the driver’s GUI.
Digital Out Device is designed as a pass-through audio path to play stereo
Hi-Fidelity audio contents or encoded audio formats such as Dolby Digital and
DTS Digital Surround bit-stream from DVD or Blu-ray disc titles. The driver do not
process all the audio data that pass through this digital device.
In most software DVD players’ audio settings, you could choose “Use S/PDIF
output” or “HDMI” for HDMI output, such as on HDAV1.3, and the players pass the
audio through the “Digital Output Device” automatically, which is better to disable
onboard audio devices first for some players. In this case, you do not even need
to change the system default audio device. Hence, in most scenarios, we suggest
that you keep it in “Speakers” to enjoy the full control functions of the Xonar sound
card. You could actually still get LPCM audio data monitoring from S/PDIF-Out port
as analog Front channel output in this situation.