(28-Jan-2022, 22:46)streamy Wrote:(28-Jan-2022, 20:35)struts Wrote:(28-Jan-2022, 18:11)streamy Wrote: Hey guys,
Have you also seen that the Phantom using RAAT play 96k/24 hires without conversion! Only 192k/24 is converted to 96k/24 and 176.4k/24 to 88.2k/24. What a great surprise! Well done Devialet!
Steady on [mention]streamy [/mention]! We’ve been here before, remember? Are you really sure?
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Yes, indeed! Could be interesting to measure if there is a change in what gets now as acoustic wave out of the phantoms? 27 kHz it should be as of specs for ‘Gold’ or 108dB Phantoms. So far I could measure roughly 23kHz as of the limited/cut sampling frequency of RAAT streams. And also all other protocols were even more restricted. Interesting times
Well, I measured my K28 Phantom I Golds running firmware 2.14.4 while playing @streamy's test signals at 24/96 (and 24/192) on Roon/RAAT. Just to be sure I also played the same files from Audirvana via UPnP.
The test comprises five 30-second FLAC files containing test tones at 1kHz, 1kHz and 25kHz mixed, 25kHz, 20kHz and 22kHz. The purpose of the 1kHz tone is to act as a 'control' and to facilitate analysis of harmonic distortion. The purpose of the 20kHz+ tones is to determine if and where low pass filtering is being applied.
The 1kHz, 20kHz and 22kHz files all played correctly showing a clear spike on the RTA plot. In no case was there any sign of the 25kHz tone, indicating that this had been low pass filtered somewhere along the way:
So my initial conclusion is that the Phantoms are still downsampling to 24/48 prior to DAC and are not lossless at 24/96, although this is not being shown in the Roon signal path so it is presumably (my assumption) not being correctly reported back to Roon:
@streamy, your thoughts?
