Phantoms not supporting anything higher than 24bits/48Khz

[struts]

I have to admit I can’t make head or tail of this.  In what way does Phantom support RAAT at 24/96 but not at 24/192?  My Phantoms at least appear to treat them identically.

I played a 24/96 cut of Nora Jones “Come Away With Me” via Roon.  The Roon signal path shows it being padded to 64 bit for SRC and then downsampled to 24/48, consistent with the published limitation of DOS 2.  The track played without problems on my K28 (mid-2017) Phantom Golds and sounded lovely. Then I played a 24/192 version of the same album, with *exactly* the same result.

Just to further add to the confusion both tracks also play without problems from Audirvana via UPnP.  So my Phantoms are not rejecting 24/192 material sent over either RAAT (which downsamples to match endpoint) or UPnP (which afaik doesn’t), even if it is downsampling both to 24/48 before conversion. 

So I would say either these inputs support 24/192 (in the sense that they will accept input programme at that resolution) or that they support 24/48 (in the sense that regardless of whether the programme is 24/96 or 24/192 it is downsampled to 24/48 for DAC).

Now I realise the 24/96 spec for the Roon input refers to the Phantom I 108 dB, so maybe there is a difference between the two hardware generations?  Could someone with the new model please rerun this test and report back?

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My Phantoms are from the series K45 and L37, so pretty old. This is what happens with "Come Away With Me":

192kHz/24Bit version:


96kHz/24Bit version:


Same for the slightly newer Reactors 600 (L45-47, "Phantom II 95dB Duo"   ) — which is apparently what Devialet claim on the updated specs. Everything sounds better than ever btw...

Quick Edit: Slightly curious why the on-device downsampling isn't marked as a "High Quality" step in the Signal Path. Maybe a marketing spin by Roon and Devialet?

Maybe I'm stating the obvious, but what I'm getting from the your screen grabs is that if you feed the Phantoms 96Hz/24Bit it does not downconvert and resample at 48Hz?  It maintains it at 96Hz?  If so that is a big improvement from what was previously being reported and/or the previous spec.

Look again.  In @DesertEagleAZ 's screenshots under the "Phantom Gold I Stereo" line (i.e. inside the Phantom) there is a downsampling from 96 to 48 in both cases.  I avoid that in my system because I am downsampling to 48 already in Roon.

[bpo]

I have to admit I can’t make head or tail of this.  In what way does Phantom support RAAT at 24/96 but not at 24/192?  My Phantoms at least appear to treat them identically.

I played a 24/96 cut of Nora Jones “Come Away With Me” via Roon.  The Roon signal path shows it being padded to 64 bit for SRC and then downsampled to 24/48, consistent with the published limitation of DOS 2.  The track played without problems on my K28 (mid-2017) Phantom Golds and sounded lovely. Then I played a 24/192 version of the same album, with *exactly* the same result.

Just to further add to the confusion both tracks also play without problems from Audirvana via UPnP.  So my Phantoms are not rejecting 24/192 material sent over either RAAT (which downsamples to match endpoint) or UPnP (which afaik doesn’t), even if it is downsampling both to 24/48 before conversion. 

So I would say either these inputs support 24/192 (in the sense that they will accept input programme at that resolution) or that they support 24/48 (in the sense that regardless of whether the programme is 24/96 or 24/192 it is downsampled to 24/48 for DAC).

Now I realise the 24/96 spec for the Roon input refers to the Phantom I 108 dB, so maybe there is a difference between the two hardware generations?  Could someone with the new model please rerun this test and report back?

Sent from my iPhone using Tapatalk

My Phantoms are from the series K45 and L37, so pretty old. This is what happens with "Come Away With Me":

192kHz/24Bit version:


96kHz/24Bit version:


Same for the slightly newer Reactors 600 (L45-47, "Phantom II 95dB Duo"   ) — which is apparently what Devialet claim on the updated specs. Everything sounds better than ever btw...

Quick Edit: Slightly curious why the on-device downsampling isn't marked as a "High Quality" step in the Signal Path. Maybe a marketing spin by Roon and Devialet?

Maybe I'm stating the obvious, but what I'm getting from the your screen grabs is that if you feed the Phantoms 96Hz/24Bit it does not downconvert and resample at 48Hz?  It maintains it at 96Hz?  If so that is a big improvement from what was previously being reported and/or the previous spec.

Okay - scratch my comments above - I guess it was wishful thinking.  Sounds like it downsamples internally and doesn't report back to Roon that it did that....  added layer of confusion, haha.

[struts]

Sounds like it downsamples internally and doesn't report back to Roon that it did that....  added layer of confusion, haha.

Er, reporting back to Roon is exactly what it is doing. Otherwise you wouldn’t be seeing the downsampling reported in the Roon signal path..


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[DesertEagleAZ]

Sounds like it downsamples internally and doesn't report back to Roon that it did that....  added layer of confusion, haha.

Er, reporting back to Roon is exactly what it is doing.  Otherwise you wouldn’t be seeing the downsampling reported in the Roon signal path..


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@struts I'm curious — what's better about Roon doing the downsampling vs. having the Phantoms do it?

[struts]

Sounds like it downsamples internally and doesn't report back to Roon that it did that....  added layer of confusion, haha.

Er, reporting back to Roon is exactly what it is doing.  Otherwise you wouldn’t be seeing the downsampling reported in the Roon signal path..


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@struts I'm curious — what's better about Roon doing the downsampling vs. having the Phantoms do it?

Haha, call it a general mistrust for Devialet software chops!  Actually it is more a trust for Roon and their ASRC algorithm.  Its configurability with options (precise vs smooth, linear vs minimum phase etc.) kind of shows that they have really thought this through and allows me to select according to my preference (which is usually for minimum phase).  As for the Devialet algorithm, well, who knows?  A black box as are most things Devialet.  Another point is just a hunch that it is better to downsample once than twice.  I can't actually back that one up with any well reasoned arguments, it just "feels" better.

[DesertEagleAZ]

Fair enough! Thanks for sharing

[quartz78]

The second change is the internal DAC capability, it was stated even for the Reactors to be 24bits/192kHz, and now it is 24bits/96kHz.
But why? What is the use of 96kHz when your DOS (DOS2)  is rated 48kHz.  And what was the kHz of the earlier operating system (DOS1) while the DAC was 192kHz.

Everybody seems to forget there is SAM processing at the end of the chain (you can see it in Roon screenshots). So it is quite possible that SAM operates at 96 kHz even if the signal is 48 kHz, and that would explain why a higher frequency DAC is used.

I'll take a risk of being shooed by all the audiophiles here, but it occurs to me that since SAM does (and always did) something absolutely unknown and potentially destructive to all those precious bits and kHz (but creating the "Devialet sound" in the process), how much does the original pristine hi def really matter in such a system?

[ogs]

One thing to remember here is that Phantoms did (does?) upsampling to 192kHz. It's part of ADH, same as Expert amplifiers. Devialet Support confirmed this to me in email (September 2020). The essence of my question was: "Is audio re-sampled in Phantom Premier and Reactor? 192kHz?" the answer was very clear: "YES, upsampling also occurs in our Phantom range of products."
I do not know if this is also the case in firmware 2.12.x.

[struts]

SAM and ADH may well be working their magic at higher sampling rates (as always with Devialet we just don’t know) but if hi res signals have been brick wall filtered at 48kHz the damage to the signal, which is in the time domain and across the audioband, is done and can’t be repaired by subsequent upsampling.


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[ogs]

Right. If upsampling is still done in the new version, it does nothing but move the filtering in the DAC to a higher frequency, further away from the music signals. I never actually liked upsampling much apart from the cases where one happened to hit a 'better' working condition for the signal chain with changed or indeed improved sound quality as result. Like the D250 Pro I owned. I preferred to send native sample rate to the amp an let it do the upsampling rather than use the Roon DSP for it. I believe Devialet made real effort to get 192kHz sampling to sound great instead of trying to get all six rates to work well (and fail).