DXD is another name for 32/352.8k PCM and we ship all tracks tagged, so FLAC is the PCM container we use (as do most). DXD is the only PCM sample rate we sell, and ONLY when the recordings are native to DXD (in some cases, DXD was used to edit a DSD recording...a purist would say it is even more direct than a reexported DSD file). Sometimes, DXD files come in a .wav container too.
DXD (352.8KHz 24/32 bit PCM) is currently the best and least destructive format for post processing DSD originated digital recordings available today. Unless mixing and balancing are performed in analog prior to digitizing, post processing is a requirement of a multi-mic'ed recording session, particularly of large ensembles. Most DSD acoustic recordings today are multi mic digitally recorded, then level balanced and mixed in DXD during post production, yielding a DXD edited master. That's then followed by converting back to DSD for consumer delivery.
DSD Files made from DXD Edit masters
Interestingly, we found after listening to DSD files made from DXD edited masters that the DSD versions, particularly the higher bit rate examples at Double Rate DSD (DSD 128fs) and Quad Rate DSD (256fs), sounded more natural, spacious, and life-like than the DXD parent from which they were made. If these observations are validated by wider listener experiences, it then points out the effects of the different processes DAC’s use in processing PCM and DSD data streams. Since the vast majority of DAC’s today are Sigma-Delta modulator based, there are less effects from the filtering necessary for PCM conversion with a DSD input.
NativeDSD is closely policing the origins of recordings and are allowing not only the DSD original files, but analogue direct transfers to DSD and DXD to be sold at NativeDSD Music. Let us be clear in that we are talking about the recording end, and that so far many people have been positive about these transfers. We are stating in the tech spec tab on each album page what is happening in the recording process.
At least 80% of DSD recordings offered on NativeDSD.com at the moment have some form of post production, which means they are most likely being converted to DXD - then through the Pyramix digital mixer back to DSD. Some labels also now record in DXD. So then it becomes acceptable to post the DXD as this is in some cases the original recording. There is a good deal of development in DSD at the moment so we invite you to keep tuned to NativeDSD and our newsletters.
Again, we will be as clear as possible to how the recording are made in the Tech Specs section of albums released in the NativeDSD Music store, but we have no control of postproduction work. If an engineer is going through the Pyramix mixer – rather than an Analog mixer, then the DSD files are being converted to DXD. Otherwise one can select DSD render where only the crossfades are being converted to DSD. We have been experimenting by taking the DXD coming out of the mixer and using that master to up-sample to higher rates. With blind testing, people have been positive about the results.