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Post by mr on Apr 9, 2018 11:27:47 GMT -5
I am playing both 2.0 & 5.1 ( FLAC and DSD) files through my XMC-1's HDMI input from my mac mini with Roon software.
Roon is telling me that the pre/pro is playing my dsf native files, ripped from my SACDs, as DoP, which I understand is DSD wrapped in a PCM file but DSD just the same.
In any case, these files sound really nice with better refined/defined bass, etc than when converted to PCM.
Or is this audio wishful thinking?
Who has the same experience? Or am I fooling myself? Would not be the first time!
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Post by Casey Leedom on Apr 9, 2018 11:37:08 GMT -5
Digital Data is Digital Data. DSD over PCM is the same DSD Data.
That said, there is a maximum Data Rate Limit for DoP dictated by PCM's Maximum Data Rate for various Media like S/PDIF, USB, and HDMI. If that isn't great enough to support the DSD's Sample Rate, then it'll have to be down converted. I'm not sure what the Maximum Data Rate of DoP on HDMI is.
In general, from the reports I've seen, you're usually best off transferring the Digital Data via USB with a Driver that doesn't need to do DoP.
Casey
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Post by routlaw on Apr 9, 2018 12:52:03 GMT -5
Hmm, it was my understanding the XMC-1 will not play DoP and that certainly has been my experience too. I am using Audirvana and not Room however but don't see why the jukebox would matter. Some DSD Dac's do not allow for the DoP so I don't think its just the XMC-1.
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KeithL
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Post by KeithL on Apr 9, 2018 14:21:46 GMT -5
There is a lot of confusion about what the various terms actually mean. DoP actually means "DSD Over PCM"... (which means DSD encapsulated in a PCM data stream). Ths PCM data stream could then be carried over any interface that works with PCM (for example a coax connection). However, when used with DACs, DoP is almost universally is taken to mean "DSD over USB" - the DSD is encapsulated in a PCM data stream, which is then sent via a USB connection. The XMC-1 does NOT accept DSD via DoP via USB (which is what most DACs mean when they say "DoP"). However, the XMC-1 DOES accept DSD via HDMI - either from an SACD disc, or from a DSD file played on a player that supports DSD output (like an Oppo; or, I suppose, a Roon endpoint). When receiving a DSD input via HDMI, the XMC-1 will show it as DSD on the display, and all processing will be disabled (the DSD signal will be routed directly to the DACs). So, if your XMC-1 is displaying "DSD" on its screen, then it is receiving DSD data directly via HDMI. And, if the XMC-1 is showing PCM audio, then the audio is being converted to PCM by your Roon. (Note that FLAC files are always decoded by your player, and sent to the XMC-1 as PCM.... the XMC-1 does not decode FLAC itself.) Three other things worthy of note: 1) The copy protection on SACD discs prevents most disc players from outputting DSD over anything except HDMI (when playing SACD DISCS). This copy protection applies specifically to SACD discs - and does not apply to DSD or DSF files. Ripping SACD discs to DSD always entails doing something to illegally bypass the copy protection on the disc. 2) There are several reasons why the SACD version of a certain album may sound different than the PCM version. - the DSD version may simply be mastered differently (in which case the CD layer on a hybrid SACD disc will sound much the same as the DSD layer on the same disc). - because PCM and DSD are not one-to-one equivalents, any time you convert between DSD and PCM, it always introduces tiny changes, which can sometimes be audible (however, that means that they're often a tiny bit different, but neither is inherently better than the other). 3) On the XMC-1, when playing a real DSD input, all processing is disabled. This can account for a significant difference in sound when switching from normal non-DSD content being played with bass management, and room EQ, active. I am playing both 2.0 & 5.1 ( FLAC and DSD) files through my XMC-1's HDMI input from my mac mini with Roon software. Roon is telling me that the pre/pro is playing my dsf native files, ripped from my SACDs, as DoP, which I understand is DSD wrapped in a PCM file but DSD just the same. In any case, these files sound really nice with better refined/defined bass, etc than when converted to PCM. Or is this audio wishful thinking? Who has the same experience? Or am I fooling myself? Would not be the first time! |
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KeithL
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Post by KeithL on Apr 9, 2018 14:39:13 GMT -5
In simplest terms..... - The XMC-1 WILL play DSD over HDMI (either from an SACD disc or from a DSD or some other type of DSD file). - The XMC-1 will only play "single rate DSD" (which is what you get from an SACD disc). - When the XMC-1 is playing DSD, it is routed directly to the DAC, and ALL processing is bypassed (if you want the XMC-1 to offer you processing then you'll have to have your source convert to PCM). - The XMC-1 WILL NOT play DSD over USB (usually referred to as DoP). (A given DAC or processor can support DSD as DoP via USB, or DSD via HDMI, or both, or neither.) (The player would matter because some player devices, and some player software, simply does not support DSD output in certain formats.... not all of them do.) Hmm, it was my understanding the XMC-1 will not play DoP and that certainly has been my experience too. I am using Audirvana and not Room however but don't see why the jukebox would matter. Some DSD Dac's do not allow for the DoP so I don't think its just the XMC-1. |
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Post by routlaw on Apr 9, 2018 14:46:55 GMT -5
Thanks Keith, and that was my understanding of what the term DoP means, but good to clarify. This begs another question… I think. So can the XMC-1 accept and play DoP via the HDMI input via a computer? I get that the XMC-1 accepts DSD over HDMI via a player like the Oppo which I have used. Or perhaps I'm missing something in plain sight.
Thanks
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Post by Casey Leedom on Apr 9, 2018 14:57:23 GMT -5
So, KeithL , what's the story going to be for the RMC-1 (and presumably the XMC-1, Gen3)? Will it accept DSD over USB? Will it be able to handle single (DSD64), double (DSD128), quad (DSD256), etc.? Casey |
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KeithL
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Post by KeithL on Apr 9, 2018 15:55:13 GMT -5
When most computers claim to support "DoP" they mean "DoP over USB" - which the XMC-1 does not support. However, any computer that says it can do "DSD over HDMI" should work with the XMC-1, and should be able to deliver DSD. I have a feeling that DSD over HDMI really is a form of DoP - but it isn't usually called that. I see no reason to suspect that a computer would be doing something different than the Oppo in that regard. However, because the way video and audio are handled inside the computer, you might want to make sure that the computer really CAN deliver DSD via HDMI. When DSD is done over USB, as DoP, the player software is sending the DSD directly to the audio device, via USB.... so the computer itself doesn't need to "understand" DSD. Audio and video via HDMI require a little more active participation from the video card and sound card.... Therefore, it's possible that certain cards, or combinations (of computer hardware) may not support DSD via HDMI.... Thanks Keith, and that was my understanding of what the term DoP means, but good to clarify. This begs another question… I think. So can the XMC-1 accept and play DoP via the HDMI input via a computer? I get that the XMC-1 accepts DSD over HDMI via a player like the Oppo which I have used. Or perhaps I'm missing something in plain sight. Thanks |
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Post by KeithL on Apr 9, 2018 16:06:12 GMT -5
OK, I'm going to go out on a somewhat narrow branch here.....  EVERYTHING FROM HERE ON IS INFORMATION THAT I BELIEVE TO BE TRUE BASED ON CURRENT INFORMATION, PROTOTYPES, AND BETA SOFTWARE.
THIS INFORMATION *MAY* CHANGE OVER TIME, AND MORE COMPLETE & ACCURATE INFORMATION WILL BE RELEASED WHEN IT IS AVAILABLE.
Everything from here on is subject to change, with or without notice, so read on at your own risk.
We EXPECT the new DC-2 to support DoP - up to DSD128 (DSDx2; double DSD). We EXPECT the RMC-1 to support both DoP over USB and DSD over HDMI up to DSD128 (DSDx2; double DSD). We EXPECT the new Processor Upgrade for the XMC-1 (the Atmos Upgrade) to add support for DoP over USB - up to DSD64 (DSDx1) to the XMC-1. So, KeithL , what's the story going to be for the RMC-1 (and presumably the XMC-1, Gen3)? Will it accept DSD over USB? Will it be able to handle single (DSD64), double (DSD128), quad (DSD256), etc.? Casey |
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hemster
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Post by hemster on Apr 9, 2018 16:43:38 GMT -5
OK, I'm going to go out on a somewhat narrow branch here..... EVERYTHING FROM HERE ON IS INFORMATION THAT I BELIEVE TO BE TRUE BASED ON CURRENT INFORMATION, PROTOTYPES, AND BETA SOFTWARE.
THIS INFORMATION *MAY* CHANGE OVER TIME, AND MORE COMPLETE & ACCURATE INFORMATION WILL BE RELEASED WHEN IT IS AVAILABLE.
Everything from here on is subject to change, with or without notice, so read on at your own risk.
We EXPECT the new DC-2 to support DoP - up to DSD128 (DSDx2; double DSD). We EXPECT the RMC-1 to support both DoP over USB and DSD over HDMI up to DSD128 (DSDx2; double DSD). We EXPECT the new Processor Upgrade for the XMC-1 (the Atmos Upgrade) to add support for DoP over USB - up to DSD64 (DSDx1) to the XMC-1. So, KeithL , what's the story going to be for the RMC-1 (and presumably the XMC-1, Gen3)? Will it accept DSD over USB? Will it be able to handle single (DSD64), double (DSD128), quad (DSD256), etc.? Casey ^These are " forward-looking statements"  |
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Post by Casey Leedom on Apr 9, 2018 16:45:05 GMT -5
Sorry, I guess I'm being dense KeithL, does this mean that we expect the RMC-1 to not handle straight DSD over USB? I.e. it'll need to be encapsulated in PCM (DoP) in order to be transfered across USB to the RMC-1? Casey |
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novisnick
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Post by novisnick on Apr 9, 2018 16:55:00 GMT -5
OK, I'm going to go out on a somewhat narrow branch here..... EVERYTHING FROM HERE ON IS INFORMATION THAT I BELIEVE TO BE TRUE BASED ON CURRENT INFORMATION, PROTOTYPES, AND BETA SOFTWARE.
THIS INFORMATION *MAY* CHANGE OVER TIME, AND MORE COMPLETE & ACCURATE INFORMATION WILL BE RELEASED WHEN IT IS AVAILABLE.
Everything from here on is subject to change, with or without notice, so read on at your own risk.
We EXPECT the new DC-2 to support DoP - up to DSD128 (DSDx2; double DSD). We EXPECT the RMC-1 to support both DoP over USB and DSD over HDMI up to DSD128 (DSDx2; double DSD). We EXPECT the new Processor Upgrade for the XMC-1 (the Atmos Upgrade) to add support for DoP over USB - up to DSD64 (DSDx1) to the XMC-1. So, KeithL , what's the story going to be for the RMC-1 (and presumably the XMC-1, Gen3)? Will it accept DSD over USB? Will it be able to handle single (DSD64), double (DSD128), quad (DSD256), etc.? Casey  |
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Post by Casey Leedom on Apr 9, 2018 20:36:29 GMT -5
Or, perhaps, KeithL, I should ask my question in a different way: what's going to be the "preferred" way to get Digital Data into the RMC-1. "Preferred" in the sense of offering support for the broadest array of Digital Formats and Resolutions? It's sounding like "HDMI" is the answer. Casey |
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Post by cwt on Apr 9, 2018 21:35:45 GMT -5
Sorry, I guess I'm being dense KeithL, does this mean that we expect the RMC-1 to not handle straight DSD over USB? I.e. it'll need to be encapsulated in PCM (DoP) in order to be transfered across USB to the RMC-1? Casey Yes ; the only reference [from Audioholics] so far differs as to the container needed for USB . Or its only semantics ; for those with large sacd libraries it would be nice to send straight dsd over the lower jitter interface even if the dsd was derived from lpcm originally www.audioholics.com/av-preamp-processor-reviews/emotiva-rmc-1-atmos-dts-x-av-processor |
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hemster
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Post by hemster on Apr 9, 2018 22:46:12 GMT -5
Or, perhaps, KeithL, I should ask my question in a different way: what's going to be the "preferred" way to get Digital Data into the RMC-1. "Preferred" in the sense of offering support for the broadest array of Digital Formats and Resolutions? It's sounding like "HDMI" is the answer. to Casey Unfortunately HDMI is the worst 4-letter word in audio/video in history! What a piece of cr@p for an interface! |
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Post by Loop 7 on Apr 9, 2018 23:18:04 GMT -5
Sounds like people are starting to buy DSD download albums or are we talking primarily about the DSD layer on an SACD when played on a true SACD player (versus the hybrid later)?
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Post by Casey Leedom on Apr 9, 2018 23:47:06 GMT -5
Hhrrrmmm, well this isn't sounding good. The RoPieee Distribution which I had planned to use only supports output over USB. But it sounds like the RMC-1 is going to require that be packaged as DoP which I believe restricts the DSD maximum rate to DSDx2 (DSD128) and only if the PCM rate supported us 384kHz. Oh, and it looks like RoPieee is also incapable of doing DoP over USB at all. It looks like it's a Feature Request. Hhmmm. This is beginning to look like a "you can't get there from here" situation ... Casey |
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KeithL
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Post by KeithL on Apr 10, 2018 9:27:35 GMT -5
USB is a packet-based interface... so you can't send "pure PCM" or "pure DSD" through it without some sort of encapsulation. Every option I'm familiar with involves some variant of DoP (I have never heard of "straight DSD over USB"). Note that, in DoP, the DSD signal is ENCAPSULATED via PCM; it is NOT converted into PCM; what comes out in the end is the original DSD. We expect to support both DSD over HDMI and DSD over USB (DoP) on the RMC-1. I have heard that there is another way to send DSD via USB - involving ASIO drivers.... I don't know the details of this method and we have no specific plans to support it. Since our new processor board used XMos USB chips, and XMos seems to be supporting this other standard, it MAY be available on the new board. I should point out, however, that DSD is a continuous data stream, while USB is a packet-based system. Therefore, sending DSD over USB will ALWAYS involve splitting the data into packets and reassembling the packets at the other end. So, the amount of jitter you end up with by doing it one way or the other is always going to end up depending on how well the process is performed. I'll be glad to check and see if it works on the RMC-1 as soon as the board itself is totally finalized. Sorry, I guess I'm being dense KeithL , does this mean that we expect the RMC-1 to not handle straight DSD over USB? I.e. it'll need to be encapsulated in PCM (DoP) in order to be transfered across USB to the RMC-1? Casey |
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KeithL
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Post by KeithL on Apr 10, 2018 10:00:50 GMT -5
A lot of this subject boils down to semantics. USB is a packet-based interface. Both PCM and DSD are continuous data streams, which means that, in order to be sent over USB, both MUST be encapsulated - or "packetized". Semantics aside.... this means that the continuous data stream must be whacked up into pieces, the pieces must be stuffed into packets for shipment, and they must be extracted and reassembled at the other end. There is no way in which a continuous data stream can be sent via a bunch of packets "directly" (imagine trying to send a roll of toilet paper in a series of first-class envelopes). In principle, DoP adds an extra level of complication, because the DSD must first be stuffed into a PCM wrapper, before the PCM wrapper is packetized and packaged for transport. Because you're "packing it twice" there's more work involved... and more work to unpack it later at the other end. It would be more elegant, and take less work, if there was some way to skip that middle step; however, elegance aside, there's no guarantee that the result would be in any way be better or different. Either way, what comes out the far end SHOULD be exactly the same as what went it; and the amount of jitter on the final output should be determined by the clock used for the final reconstruction step. You may also be under a misapprehension that DSD is somehow inherently lower in jitter than PCM..... which is simply untrue. Since, in either case, the audio stream has to be split into packets, and then reassembled at the other end, the amount of jitter you end up with is going to depend entirely on the quality of the reassembly process. I should also note that, from a PURIST point of view, if the original was PCM, then the best solution would be to minimize the number of conversions, and LEAVE IT AS PCM. And, if you simply like the way it sounds better after all that mussing around, then the best solution would probably be to avoid further conversions. (However, if your content started life as PCM, then it would be pretty silly to suggest that "DSD is better than PCM and you'll ruin it by converting it to PCM" now wouldn't it?) To answer your question directly, however, there is no such thing as "straight DSD over USB" because DSD is a continuous data stream and USB is not. (There are just different ways of encapsulating DSD so you can send it over USB....) To be totally honest here, and answer your question as well as I can.... We do NOT consider DSD to be an especially high priority. We DO plan to support DoP - because there is a small but significant amount of demand for it. Whether we support any other methods will probably be determined by whether they are inherently supported in the new XMos USB audio solution we're using. (If they're "part of the package provided by the XMos solution" then we'll support them.) In terms of semantics, when WE describe "native DSD decoding" we're referring to the fact that.... THE DACS IN THE XMC-1 AND THE RMC-1 DECODE DSD DIRECTLY WHEN THEY RECEIVE IT RATHER THAN CONVERT IT TO PCM FIRST.Sorry, I guess I'm being dense KeithL , does this mean that we expect the RMC-1 to not handle straight DSD over USB? I.e. it'll need to be encapsulated in PCM (DoP) in order to be transfered across USB to the RMC-1? Casey Yes ; the only reference [from Audioholics] so far differs as to the container needed for USB . Or its only semantics ; for those with large sacd libraries it would be nice to send straight dsd over the lower jitter interface even if the dsd was derived from lpcm originally www.audioholics.com/av-preamp-processor-reviews/emotiva-rmc-1-atmos-dts-x-av-processor |
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Post by routlaw on Apr 10, 2018 11:04:36 GMT -5
At the risk of sounding cynical and derogatory am I the only one who thinks all this has gotten way out of hand with complexity? I read through a couple of threads on the PS Audio forums that were very similar awhile back and likewise they were also this complex. The computer audiophile forums, same thing. Seriously when did listening to music ever get to be this convoluted, impenetrable and complex? Is it any wonder that iPods, and mobile devices with a pair of ear buds has stolen the hearts and minds of at least a couple generations of music lovers.
For me it somewhat takes the fun out of it. Makes spinning vinyl and red book cd look like a walk in the park which it is by comparison.
Note this is not a negative comment to anyone who has contributed to the thread, just the concept and the situation itself. Keith your knowledge and expertise is appreciated.
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