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Product Support => HiMedia Q10 Pro, Q5 Pro => Topic started by: Mount81 on November 13, 2016, 11:10:08 AM

Title: SPDIF LPCM output compatibility
Post by: Mount81 on November 13, 2016, 11:10:08 AM
Hello!

I'm using the Q10 Pro's analogue RCA outs to get sound with my active pair of stereo speakers. Works fine so far. But I'm into a bit "upgrade" sound qulaity wise -if it's idea proofs worthy and working-, and planning to buy an SPDIF DAC like this one: http://www.fiio.eu/index.php?route=product/product&path=61&product_id=57 (http://www.fiio.eu/index.php?route=product/product&path=61&product_id=57). If I set the SPDIF output to LPCM will this DAC be able to produce sound from it in the cases of DD, Dolby, DTS, DTS-HDMA as well? As far as I know all sound formats -except HD sounds- can be transcoded to stereo PCM, so this DAC could receive a compatible format and decode it to analogue?!

Am I rightn or are there more limitations with this method regarding the compatible -and transcodable- audio formats?!

Thanks for the replies!
Title: Re: SPDIF LPCM output compatibility
Post by: Mount81 on November 15, 2016, 09:56:32 AM
(No petulance, but) 84  wievs and no one had a clue jet? ???
Title: Re: SPDIF LPCM output compatibility
Post by: Mount81 on November 20, 2016, 02:53:57 PM
Had to UP the topic. :-\
Title: Re: SPDIF LPCM output compatibility
Post by: futeko.com on November 21, 2016, 09:44:21 AM
You'll have gathered by now that I don't know the answer for sure..

What I think would happen is that high bitrate PCM/LPCM audio will pass as source and the DAC will convert to stereo, but DD, DTS, DTS-HD MA etc will be downsampled to stereo 48Hz by Q5/Q10 Pro before output by SPDIF. So for DD, DTS, DTS-HD MA you'll not get much of a quality improvement.

In general I wouldn't have thought the quality improvement of a cheap external SPDIF DAC like that would be very big vs using Q5/Q10 Pro's RCA outputs.
Title: Re: SPDIF LPCM output compatibility
Post by: Nice Monkey on November 21, 2016, 09:52:15 AM
You'll have gathered by now that I don't know the answer for sure..

What I think would happen is that high bitrate PCM/LPCM audio will pass as source and the DAC will convert to stereo, but DD, DTS, DTS-HD MA etc will be downsampled to stereo 48Hz by Q5/Q10 Pro before output by SPDIF. So for DD, DTS, DTS-HD MA you'll not get much of a quality improvement.

In general I wouldn't have thought the quality improvement of a cheap external SPDIF DAC like that would be very big vs using Q5/Q10 Pro's RCA outputs.
There is something strange with the pure Audio handling also using the standard Music Player (and others).
When playing 16-bit 44/48 KHz material output is LPCM and passing internal processing (volume control interacts). When playing FLAC at 24-bit and 96/192Hz output is RAW in LPCM or MCH matching the source material (not volume controlled). This with Output set as RAW on SDIF/HDMI.

This has been reported since the original release but never addressed.