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Full Version: [WINDOWS] Why do 5 channel WAVs get downconverted to 2 channel?
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I'm trying to achieve bitperfect playback on my W7 system, and it seems unclear as to whether it's even possible. So, to test, I have several multi-channel WAV files in either AC3 or DTS codecs. Much to my surprise, they play, but they are downconverted to 2 channel stereo via SPDIF to my receiver.

Usually, if playback software or windows is allowed to touch the stream at all, I will hear static from the receiver, as the stream is being tampered with by a whole host of external factors such as the audio card, a windows mixer, etc. Is there a setting I'm missing that would allow the stream with all its 5 channels to pass to the receiver without mixing them to 2 channels?:confused2:
floepie Wrote:I'm trying to achieve bitperfect playback on my W7 system, and it seems unclear as to whether it's even possible. So, to test, I have several multi-channel WAV files in either AC3 or DTS codecs. Much to my surprise, they play, but they are downconverted to 2 channel stereo via SPDIF to my receiver.

Usually, if playback software or windows is allowed to touch the stream at all, I will hear static from the receiver, as the stream is being tampered with by a whole host of external factors such as the audio card, a windows mixer, etc. Is there a setting I'm missing that would allow the stream with all its 5 channels to pass to the receiver without mixing them to 2 channels?:confused2:

There's an option in the music (or audio) setting screen to downmix multichannel to stereo. Disable this option.
Yep. It has always been unchecked. So, these 44.1 kHz 5 channel WAV are downmixed, but oddly, the 48 kHz AC3/DTS tracks of movie files get through just fine.
floepie Wrote:Yep. It has always been unchecked. So, these 44.1 kHz 5 channel WAV are downmixed, but oddly, the 48 kHz AC3/DTS tracks of movie files get through just fine.

The SPDIF spec does not allow for more than 2 PCM channels.
Right, but they're not PCM. They're encoded in either AC3 or DTS and that just so happen to be WAV files. A 5-channel WAV DTS file, which can be sourced all over the internets, is the gold standard for bitperfect test to one's receiver in order to verify that bitperfect output via SPDIF has been achieved.
You can only use 48 kHz for passthrough as far as I know.
But, what's interesting is that the WAVs are being decoded before they are sent to the receiver, and the PCM stream is being sent to the receiver, as I can clearly listen to the files, albeit in 2 channels. I have never come across a player which decodes a 44.1 kHz DTS file. :confused2: