Q8: What's the application of "S/PDIF in loopback"?

Answer:

"SPDIF in loopback" is the process of looping back the sound card's S/PDIF digital input signal directly to the S/PDIF output. It's useful mainly for two purposes:

•transforming electrical signals from coaxial cable to a fiber optical cable, or vice versa.

•using the PC as a SPDIF bridge (typically as a media center): for example, connect other devices like DVD players to the Xonar D2’s S/PDIF input and then connect its SPDIF output to an AV receiver or decoder. When you would like to send the player device's audio to the AV receiver, you need to have the Xonar sound card's "S/PDIF in loopback" enabled to redirect the player's input signal to output to the AV receiver.

Since "SPDIF In Loopback" is the hardware’s high-fidelity pass-through path, not all sound effects will be applied to the signals.

Q9: Will PCM sound output through S/PDIF be just 2 channels even with different analog output channels?

Answer:

The S/PDIF protocol specification (IEC-60958) can only carry 2-channel PCM data or non-PCM AC3/DTS data. So, when a user selects PCM output for S/PDIF, the Xonar sound card will always deliver 2 channel PCM data through the S/PDIF output port. For attaining 5.1 channel surround sounds, you can select Dolby Digital Live or DTS Interactive encoding output from the S/PDIF out menu, which will allow the Xonar D2 to deliver 5.1 surround sound for games, DVD movies, and even stereo music.

ASUS Xonar D2

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