This has been an interesting exchange. I may chime in about RVG later, but for now I’d like to add a comment about what folks may be hearing in DSD256 vs. DXD (352.8kHz 24-bit PCM). First, I fully endorse the notion that Pure DSD256 is the finest sounding audio format we currently have available to us. It is just observationally closer to what the microphones hear than any other format. But, my listening experience also has convinced me that many of the differences we hear are related to how our equipment handles the digital signal stream, whether PCM or PDM (the format that includes DSD).
The hardware and the algorithms that decode the digital stream vary for piece of gear to piece of gear. Some do better handling the PCM stream, others the PDM (DSD) stream. Some convert everything to PDM as part of their internal processing, as is the case with my Playback Designs MPD-8 DAC (circa 2019).
Because there are so many variables, I’m going to limit my comments below just to Bob Witrak’s HDTT releases:
Bob releases some Pure DSD256 files which were converted to DSD256 directly from 2-track tape using an Emerging Technologies analog-to-digital converter (ADC). He then releases the resulting DSD256 file without any PCM processing. It is Pure DSD256 from the analog tape. These are frequently the best sounding files HDTT releases. He will additionally convert these files to various flavors of PCM (96kHz, 192kHz, and 352.8kHz) to meet market demand. Most of these are jazz recordings because he has more success finding clean sounding jazz source tapes that can be released without further post-processing. For me, these are the “Gold Standard” among the HDTT catalog.
But I am a classical music lover. And I love his catalog of classical recordings, with some of the greatest recordings ever made. So, what happens here?
Many of the classical source tapes need work. Not all – but the tapes that can be released without some post-processing are the exceptions, even the direct dubs from the studio masters. So, Bob starts as he always does: a DSD256 transfer of the source tape. Then it gets converted in the Pyramix Digital Audio Workstation software to 352.8kHz/32-bit PCM (“DXD”) for clean-up. The type of cleanup and the software tools used in doing this will vary depending on what work is needed to bring the final product up to Bob’s standards. Usually the issue is background noise that needs to be filtered. But sometimes it is pitch, sometimes a bit of frequency balance adjustment here or there. This is all done by ear to Bob’s tastes. If the project requires some particularly intensive post-processing help, the work may get outsourced to the very capable John Haley, a restoration magician if ever there was one. Again, the work is all by ear.
Once a final PCM edit master has been completed, the file is ready for publishing in any of the various formats released by HDTT: 352.8kHz/24-bit (DXD), 192kHz, 96kHz, DSD64, DSD128, DSD256. The web page for the release ALWAYS tells you whether the file has been post-processed in DXD. If it is Pure DSD, the page will clearly state that.
Now…, why am I going into all this long detail? So that this next statement may make some sense.
In my primary system, from the various HDTT releases, I always hear what I consider to be the most accurate music reproduction when I listen to the edit master. If the edit master is Pure DSD256, then that’s the one. But if the edit master is a DSD256 transfer that has been post-processed in DXD, then it is the DXD file. Heard through my Playback Designs MPD-8, the edit master DXD file will sound better than the DSD256 file that Bob has created from that DXD edit master file.
Why? Two reasons: (1) one fewer file conversion, there are always artifacts; and (2) my DAC is going to convert the DXD file into DSD256 automatically and it does a better job converting from DXD to DSD than does the Pyramix software Bob uses.
So, for me, in my system, the DXD edit master file will sound better that the HDTT provided DSD256 file.
On the other hand, in my wife’s office system, using a Teac 508 DAC, the HDTT provided DSD256 file sounds better. Why? Different DAC, different internal hardware, different algorithms. The Teac DAC is optimized for playing DSD.
All of this is just to say: everything we hear is SYSTEM DEPENDENT. I believe DSD256 is objectively superior in sound quality to PCM. But what we actually hear in our systems is system dependent, not absolutes.
And kudos to @dchang05 for making his observations abundantly clear: in his Grimm MU2, the sound of DSD is better than the sound of PCM. My guess is that the DAC is optimized to play DSD. And what a great place to be if one has to choose!
