You should disable mixer when using HDMI and let the receiver do the upmixing.
You should mix to stereo when using S/PDIF, as that does not support more channels for PCM audio. Bitstreamable formats (AC3/DTS/etc) will be passed through untouched.
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i work wite S/PDIF or HDMI ( amd or NVIDIA VIDEO CARD )
You should disable mixer when using HDMI and let the receiver do the upmixing.
You should mix to stereo when using S/PDIF, as that does not support more channels for PCM audio. Bitstreamable formats (AC3/DTS/etc) will be passed through untouched.