News

Promates: The World's First DXD Download Store

Jason Victor Serinus  |  Dec 10, 2014

The world's first download site devoted exclusively to ultra hi-resolution DXD downloads, Promates Music Store, has launched from Copenhagen. The brainchild of Peter Scheelke, who in 2003 helped found Digital Audio Denmark (DAD), creator of the world's first commercial DXD converter, the site currently offers 26 native DXD recordings (352.8kHz sampling rate and 24-bit bit depth) from labels Dacapo and OUR Recordings.

"We have to make people aware of DXD," Scheelke told Stereophile via Skype. "I'm starting off with enough material for people to test. Once people are aware of the format and the store, I'll go to the labels and request more material. I know they have the converter to record directly to DXD, because I created it."

According to Scheelke, the reason it has taken until now to launch a DXD music store has to do with file size. While the size of a typical DSD album file is approximately 1.5GB, a DXD album often exceeds 5GB. Thankfully, faster download speeds and large storage have now made DXD downloads practical. Promates thus joins Norwegian label 2L, whose 2L Music Store offers DXD downloads of all its albums, dating back to the February, 2010 recording of Ole Bull Violin Concertos.

"The sound is softer and warmer than DSD,” Scheelke claims of DXD. "It's far more calm and analog-like."

Scheelke explains that the DXD format arose from the need to make an editing system for DSD that would have minimal impact on sound quality. Scheelke’s company offered to build a converter for Merging Technologies, whose Pyramix system is used to edit and assemble DSD masters, that would record directly to DXD. From this arose Merging Technologies' Sphynx 2, an A/D converter that DAD built for them in 2004 as an OEM product. Also released by DAD under the name AX24, the unit was capable of creating digital files in DXD, 384kHz, DSD, and DSD128 (double DSD) formats, as well as PCM from 44.1kHz to 192kHz.

"The problem is that if you are doing a recording in DSD (1-bit, 2.8224MHz sampling rate), you cannot edit in DSD, because you cannot edit a 1-bit stream," Scheelke says. "So you need to convert to DXD, and then convert back. Each time you do so, you add a new amount of noise.

"DSD has a major problem with out-of-band noise. Without a noise shaper, DSD noise is around 85dB in the whole frequency range. Each time you convert DSD to DXD and then back again, the noise will raise and raise and raise. Eventually, because of the noise, DSD will no longer comply with the Scarlet Book definition of DSD. This is why someone like Michael Bishop does his mastering while he's recording. It's one take, and that's it. This strategy eliminates the extra out-of-band noise."

To back up his statements, Scheelke has posted a long paper on ProMates that discusses the store's audio formats and their characteristics. To underscore the superiority of DXD, he also includes three graphs that detail what occurs in A/D conversion. The paper concludes with the following statement:

For me, it is clear that there is an undeniable relationship between resolution and quality. Each format seems to have has its own expression and conversely, its own limitations. To reproduce classical music, for example, I have always preferred the quality of DSD.

Yet, it was not until I experienced DXD that I was no longer able to hear the signal as a digital reproduction. In contrast, DXD is calm and warm, with a deep, resonant and well defined stereo perspective. So much so that it evokes memories of the heady days of analog.

The Promates Music Store contains two different recordings of symphonies by Carl Nielsen. Both are performed by the New York Philharmonic under Alan Gilbert, and recorded in the same hall using the same microphones. The major difference is that while the file of Symphonies 2 and 3, which was issued as an SACD, was recorded in 88.2kHz due to a customs snafu that slowed the import of DXD equipment into the US, the subsequent recording of Symphonies 1 and 4 was done directly to DXD. Perhaps microphone placement was a bit different on the second go-around due to increased familiarity with the hall, but that and the digital format are the only difference.

Scheelke encourages audiophiles to download both recordings and compare the sound. Although my ability to do so was limited to desktop and headphone listening, the Audeze LCD-2 headphones, abetted by Nordost Heimdall 2 headphone cabling and connected to an Antelope Zodiac Gold DAC, clearly conveyed the greater atmosphere and depth of the DXD recording.

"When you compare DSD to DXD, the DSD is quite good," he says in conclusion. "If you do all your recording in DSD, and only convert to DXD once for mixing and editing, it will sound quite good on most equipment, depending on the limits of the amplifier and converters. But I've been in most of the best studios and listened and listened, and if you have a DSD file that you edit in DXD and then convert back to DSD, and you compare it to the original file, you can hear what you've lost. For that reason alone, since DXD is the format you are using when you create an SACD from DSD files, then it more than justifies listening to DXD by itself.

"The only reason to use DSD is that you get a smaller file, because DXD is better. No disc can hold a DXD album. This is why no one knows about it, because it has to be downloaded. Most of the guys who produce SACDs do so from DXD files. I know this for a fact, because I probably sold them the converter they are using. There are thousands of recordings in DXD out there—probably half the SACDs out there were recorded in DXD on a Pyramix system—but no one has heard them in the DXD format."

Peter Scheelke is out to change that. As far as he is concerned, DXD's time has come.

COMMENTS
doak's picture
Submitted by doak on December 10, 2014 - 5:59pm

.... is well underway !! :D

Mr. Sheelke's explanation makes complete sense to this lifelong music lover/audiophile. "The closer to the source, the more realistic the recording" has always held and I expect will always hold true.
I've been praising and stuck on DSD lately but will be downloading some DXD this evening.

About 2 weeks ago I corresponded with the proprietor of a different hi res download site as to why he did not make the source DXD files available for selections that were noted to be originally recorded in DXD. His response was "There is no market for the DXD" so he offers them as DSD. ProMates and Mr Scheelke may very well prove him wrong and short sighted.

Hi-Reality's picture
Submitted by Hi-Reality on December 10, 2014 - 5:32pm

Thanks for the news. Looking absolutely forward to download and test some Promates DXD files for the Hi-Reality project.

Founder & Project manager,
The Hi-Reality Project
www.hi-reality.org

Jason Victor Serinus's picture
Submitted by Jason Victor Serinus on December 11, 2014 - 10:52am

When I conducted research for this article, I looked at the menus on 2L's Music Store page and saw nothing about downloads. Hence, I accepted Peter Scheelke's claim that they were not available. Now, following a most gratefully received message from Bruce A. Brown of Puget Sound Studios, I return to the 2L site, click on individual albums, and discover my error. Every 2L project recorded in DXD, from Ole Bull on, is available in multiple download formats, including DXD. My sincerest apologies to Morten Lindberg and Stereophile readers. We have fixed the copy.

Hi-Reality's picture
Submitted by Hi-Reality on December 11, 2014 - 3:38pm

Thanks Jason for yet another interesting update. It makes me more happy that DXD has now two stakeholders from two Scandinavian countries: Norway's 2L and Denmark's ProMate. Coming from Sweden (and stationed in Irvine, CA, since 5 years ago) I aim to explore potential collaborations with both in making the Hi-Reality project an extraordinary experience.

Cheers & Skål (Skoal) !!

Jason Victor Serinus's picture
Submitted by Jason Victor Serinus on December 11, 2014 - 11:03pm

What a great and positive comment. Perfect for the holiday season. Gratefully received.

Kal Rubinson's picture
Submitted by Kal Rubinson on December 14, 2014 - 4:09pm

Since Bruce raised the issue, let me point out that (1) nativeDSD.com has been offering DXD files for some time now and (2) both NativeDSD.com and Promates are offering other formats, as well. So, I would say that no site is "devoted exclusively to ultra hi-resolution DXD downloads."

remlab's picture
Submitted by remlab on December 11, 2014 - 1:45pm

..until the sample rate's 705.6kHz. (Kidding..kind of..)

tnargs's picture
Submitted by tnargs on December 12, 2014 - 1:48am

So just drop the DXD rubbish, thank you!

jmsent's picture
Submitted by jmsent on December 12, 2014 - 5:14am

of DXD compatible DAC's already in the marketplace? Something tells me this number is tiny.

audiolab's picture
Submitted by audiolab on December 12, 2014 - 7:46am

and its great you have updated the article to include 2L, now how about updating the Headline title to match. Anyone who has not visited the 2L website should do so, there are masses of FREE downloads in just about every conceivable format/bit rate/bit depth etc known to mankind.

deckeda's picture
Submitted by deckeda on December 12, 2014 - 9:23am

The DXD moniker has been floating around for several years. As tnargs noted, it's PCM but happens to be a multiple of 48 instead of a multiple of 44.1.

What's new is they're now directly selling the file to the public, to those whose DACs know what to do with a 352.8kHz file. Is that a popularly-supported resolution?

Regarding its historical significance as an editing platform for DSD recordings, that too is of course a product of marketing because you could also convert a DSD file to say, 192kHz or 384kHz PCM if you wanted to edit it.

Axiom05's picture
Submitted by Axiom05 on December 12, 2014 - 10:15am

Actually it is 8 x 44.1 not 48 which is probably why it is preferable for conversion to DSD.

corrective_unconscious's picture
Submitted by corrective_unco... on December 12, 2014 - 11:16am

About every time there's a new format or new flavor of a format you need to buy a new DAC and "need to" buy your music again in that new format.

This gets really fun when it's hard to be sure that SACD was, past tense, all that much better than Redbook, or when it's hard to be sure that DSD in all its manifestations and DXD in all of its are better than PCM at, say, 24/192. (Oh right, DSD needs so little processing to be turned back into music....)

Normal consumers are not driving any of this stuff that goes beyond 24/192. It will also be fun to watch most of these various flavors go the way of 3D TV. We should be seeing lots of 24/96 max DACs at thrift shops real soon now. Not on the various audio shopping web sites...at thrift shops.

But of course if I go into the hardware business I will come here and edit this comment into oblivion and then set about removing money from your wallets.

Jason Victor Serinus's picture
Submitted by Jason Victor Serinus on December 12, 2014 - 12:46pm

Jared Sacks' NativeDSD.com site only sells files from companies who record in DSD. That does not mean that their material was not converted to DXD at least once, if not more than once, for editing purposes, and then converted back to DSD. But the master recordings originated in DSD, not PCM. SACDs sourced from PCM masters are not sold at NativeDSD.com. So that is your reference.

corrective_unconscious's picture
Submitted by corrective_unco... on December 13, 2014 - 9:39am

Assuming you even meant to reply to my post....

My post was not about whether a particular file originated in this or that format, or was converted in a deleterious manner.

My post was about the need or real benefits of all these yet again new formats - plural - relative to the costs of the new hardware and software purchases.

Any advantages of SACD over Redbook were debated by many, imo. The practical significance of any advantages of DSD or DXD for most audiophiles as compared to 24/192 PCM is also debatable, imo.

The additional expense all these new formats impose over PCM for consumers is not debatable. That is a simple fact. A fact that I'm sure purveyors of hardware and software are counting on.

I doubt average audiophile consumers (oxymoron) are driving demand for DSD and DXD, except for the usual hard core early adopters whose entire identity hinges on participating in such never ending evolutions/gambits.

doak's picture
Submitted by doak on December 15, 2014 - 7:22am

"I doubt average audiophile consumers (oxymoron) are driving demand for DSD and DXD, except for the usual hard core early adopters whose entire identity hinges on participating in such never ending evolutions/gambits."

Or music lovers who are interested in experiencing what is possibly the absolute HIGHEST quality digital music reproduction available to them in their homes.

corrective_unconscious's picture
Submitted by corrective_unco... on December 15, 2014 - 5:38pm

I'll be cackling with glee as this handful of ultra early, pavlovian adopters buys all new DACs and lots of (possibly, it might not really be) DXD or DSD music and wind up in another dead format end.

Spend away!

Jason Victor Serinus's picture
Submitted by Jason Victor Serinus on December 12, 2014 - 12:41pm

And there you have it.

Swineshead's picture
Submitted by Swineshead on December 12, 2014 - 1:24pm

I've got the next generation of DAD converter: the AX32. It is absolutely fantastic! Like the AX24, the AX32 is neutral and for me like lifting a veil off recordings, compared to what I had been using previously. Denmark rules!!

rompolompo's picture
Submitted by rompolompo on December 13, 2014 - 1:47pm

There is no benefit for these high sampling rates. We cannot hear or feel them. There is an exception if you are an audiophile german shepherd.

Jason Victor Serinus's picture
Submitted by Jason Victor Serinus on December 13, 2014 - 6:17pm

I think I've just been called a dog... Our three pooches will be proud of my new status, and undoubtedly attribute my transformation to canine superiority.

Roger That's picture
Submitted by Roger That on December 14, 2014 - 5:52am

I hope that I’m wrong on this one, but this looks like another (very) unlikely success.
IMHO, the “audio industry” has been unable to do any remotely similar to what the “TV industry” has done. Huge amounts of people jumped into the 16:9 format (which had a huge help and also helped DVDs), only to push new content and equipment with the HD TV (1080p) format. And even if the 3D was a relative failure (I never expected anything else from it), they are already pushing the 4K format into consumer minds.

I would risk a guess on why the audio industry has failed massively at doing the same:

A) Unlike audio, no one needs to have “golden eyes” or extensive training to clearly see the difference between a DVD source vs a 1080p at any reasonable bitrate. This means that there are real and big performance differences between technologies.

B) It all happens within the indisputable range of what any person (the average Joe) can testify. Even if we would hide the information about the resolution of each video file/sample, most people would clearly differentiate a SD vs a HD video file on an A/B comparison. This also means that the video industry needs to be (and it is) clearer about the sources, and clearly mention when a HD file was upsampled from SD (older) material. The audio industry has been (a lot more) obscure about those “details” on HRA content.

C) The Compact Disc was built around solid technical arguments, and all formats that added resolution above that proved to be unappealing for most consumers. If the real perceived audio difference between a redbook specs and HRA was nearly has big as the ones we see on TV/video, we would be beyond a huge success. But that’s a big “if”…

corrective_unconscious's picture
Submitted by corrective_unco... on December 14, 2014 - 12:31pm

1. In the switch from 720 to higher resolution televisions the extra money was not that great, all other things being equal.

2. The jump did not require all new software (content) to take advantage of what gains there were.

3. There were not (for long) a multiplicity of resolutions and file formats, the way we now have with dsd flavors, dxd flavors, pcm flavors.

4. It also warrants noting that tv buyers are confused: They don't realize the higher resolutions add very little for cable or sat broadcast content because that content is so lossy-ily compressed. So the people who idiotically went for 3d and who are now early adopting 4k are exactly the ones I was speaking of in my posts above, i.e., people who are not reflective of any genuine or mass consumer need. It here also is more about a consumer electronics industry segment desperately trying to create a largely false "need" in order to gin up revenues.

Roger That's picture
Submitted by Roger That on December 17, 2014 - 10:51am

I’m sorry, but I respectfully disagree with you on several points.

1. The big switch was from SD to 720p, but with any bigger TV screens, you can clearly see the improvement of 1080p over 720p. On video projectors this is hugely amplified. Now bear in mind that 1080p TV’s don’t carry a huge price increase over 720p, making it easier for the “average” customer to pay a little more for higher resolution/technology.

2. The jump did require new content from the TV and movie industry, along with new formats: Bluray, HD DVD, video streaming (renting) from cable providers at higher resolutions. There’s so much you can do with a 1990 show recorded on PAL or NTSC analogue video… ;-)

3. You have several file formats, or at the very least, video containers. MP4, MKV, MOV, M2TS (just to name a few) along with several kinds of audio formats (from 2 channel mp3 to AC-3/DTS/5.1 AAC/DTS-MA/ Dolby Digital HD, etc). And some of these formats (like MKV) are still adding new features, not always compatible with every kind of media player, be it a standalone or integrated on the TV set.

4. We can surely argue if TV buyers need all this, and it sure helps to confuse people. But bear in mind that 2013 was the first year that TV sales have declined, while audio sales have been declining for years in a row. This is most likely the result of several factors, but it may also be related to the fact that any SD vs 1080p comparison will held obvious results for almost anyone, which does not the case with HD audio over the CD redbook standard. That’s not to say that they sound the same, but it lacks the ‘wow’ factor and the urge to upgrade.

That being said, I’m only sharing my thoughts and humble opinion, and I do wish that reality will prove me wrong.
I still hear more music on an average day than I watch TV during one week (sometimes in one month)… :-)

I wish you all a merry Christmas.

corrective_unconscious's picture
Submitted by corrective_unco... on December 22, 2014 - 8:48pm

The new software, that is, programming, did not _require_ the purchase of new TVs.

Many people felt they needed new TVs, or elected to get new DVD players, etc. That's a different point from my one about TVs.

I do note the declining sales of consumer electronics generally, however, which to me supports my contention about false, marketing driven "needs" for new stuff. And it's true that audio isn't the only area with formats or technologies which died early and amusingly left a lot of early adopters' hardware and software stranded.

Roger That's picture
Submitted by Roger That on December 14, 2014 - 5:54am

I must say that I’m not nearly a “video” fan as I am an “audio” fan. I’m like John Miles (“music was my first love and it will be my last”), and I’ve spent way more money on audio (from musical instruments, recording equipment to Hi-Fi gear). But I still “had” to buy a 16:9 TV, a DVD player, then a 1080p Plasma, then a 1080p projector, etc…

Do I have any DSD dac?
No, and I don’t really miss it!

Why? Mainly because I still believe (even from my audio recording perspective) that most bad sounding CD’s (or 44.1/16 if you wish) sound like they do because they were meant to sound like that! Those were mixing and mastering decisions, and not any kind of limitation from the audio format.

High Resolution Audio could be viable if the music industry was willing to remaster (and sometimes remix) most content in order to really make a difference. That would be a way to give people a reason to buy the same music all over again, and invest on HRA capable audio gear.
But with the current path, I must say (with some sadness) “good luck with that”.

deckeda's picture
Submitted by deckeda on December 15, 2014 - 4:54am

In either case the buyer first has to care. I know plenty of people who won't spend a dime getting a nicer TV. You can recommend specific models to consider and it won't matter. They won't seek out the nicer picture, that is why they don't understand or believe in it.

Audio is really no different, because it's also a hobby, so forget about golden ears and Nyqvist and all that other mental masturbation and "explanations" intended to substitute for caring.

All of these file permutations today are the result of the music industry abstaining from the effort to guide the market. No label has embraced hi res files in any consistent way. The standard today isn't even the CD, it's lossy downloads and that's what's good enough to be their mainstream product. To them, the rest is just pre-recorded "open reel, 8-Tracks and cassettes" -- alternatives to the main product.

Contrast that with the 1940s, where a major label was the only entity with the tech and the desire to create a new format where quality was -- perhaps by accident (or necessity?) -- a major leap forward. We also got consistency in the bargain.

In the back of everyone's mind, whether you're a seller or a buyer is the eternal hope and promise of getting back to One Format We Can All Gather Around so that spend less time worrying if our DAC will play something and more time playing something.

doak's picture
Submitted by doak on December 15, 2014 - 5:30am

My $500 Audio-GD DAC handles DXD and DSD64/128 and sounds very good "in the process." I've also have a Lampizat0r Amber DAC on order that promises to do the same while, hopefully, sounding even better.

After perusing the ProMates online store extensively I have submitted the following though their support channel. I offer it here for discussion and possible responses:

Title: Provenance of Music Albums offered for Sale

I am MOST interested in having information on the original recording format of the individual albums you are offering ofr download. I want to download in DXD, though beforehand I would very much wish to know the provenance of that particular item. For instance I am interested in downloading "An Amerikaner in Danmark" in DXD. Question: Was the original recording done in DXD? If so, was the DXD format retained in the edit/mix/mastering stages? This is the type of info now necessary to ensure what one is getting is what one is paying for. At least, if is information that absolutely should be made available to the end consumer of ALL music files. Please advise me on the cited album. I am enthusiastic about this service. Work with me and I will work with you. Best Regards.

MUCH to his credit, Peter replied to my "open ticket" within minutes. Here is his response and it is EXACTLY what I wanted to know:

"Hi Doak

All albums except Carl Nielsen 2-3 was original recorded and edited in DXD. That is a major point with the site.
Sample rate conversion has not been used at DXD files. So, a multi-track DXD recording has been mixed down to stereo, and then compressed with lossless FLAC, and everything is then collected in a zip file. That’s all.

Carl Nielsen 2-3 was original recorded in 88.2. It was released on an SACD, but We have only added the 88.2 version to the site. Not the DSD version."

doak's picture
Submitted by doak on December 15, 2014 - 10:02am

The 4.8GB ZIP file came down in about 20 minutes. I extracted the files, cued them up in JRiver and they've played perfectly without a hiccup.

"Awesome" is a word I use infrequently but it is totally suitable for what I am hearing. What we have here is basically the "master tape." How often do we get to listen to, much less own, the master tape of an album/performance?

The recording is deep, spacious, detailed, clean and clear. It will stretch and probably tax the limits of your music reproduction system. I've listened to and through it twice and can't get the silly grin off of my face. I may have to give it rest soon however since it may be causing some trauma to the cats sequestered in an adjacent room. ;-)

corrective_unconscious's picture
Submitted by corrective_unco... on December 15, 2014 - 5:54pm

That certainly refutes my point about early adopters buying a new DAC.

I think the odds that your $500 DAC actually keeps a (claimed) DSD file in DSD all the way through, or that you are able to understand this point, would be very small. (Who knows about DXD? That's a kind of PCM.)

Here's some help understanding this:

"The 2014 NFB-3’s USB input is fully UAC 2.0 compliant – driver-less on Linux and OS X – and it can handle PCM up to 32bit/384kHz (DXD) and DSD (although the specifics on this are a little vague at this stage). Windows users will need to download the Audio-gd driver. Coaxial and BNC inputs hit a glass ceiling of 24bit/192kHz."

You can see what product it is a review of.

digitalaudioreview DOT net/2014/04/audio-gd-update-nfb-3-dac-with-ess-sabre-9018-chip/

doak's picture
Submitted by doak on December 15, 2014 - 6:09pm

Using the Audio-GD ASIO USB driver the NFB-3 does confirmed native DSD64/128 and DXD 24/352 and manages to sound damned good doing so. Disregard what it costs. In my experience, it is as good or better than anything at 2-3X its tiny price.

BTW: The review you cite is for a previous iteration (old version). I'm using the NFB-3 (2014)

corrective_unconscious's picture
Submitted by corrective_unco... on December 16, 2014 - 9:11am

The model number is right there in the quote I pasted.

So let's find out more about your claims: What OS are you using, which driver rev. from that DAC's manufacturer, and are you exclusively using USB to connect? If your NFB-3 is a new iteration compared to the one referenced in the quote then exactly what model number is it?

Then we can pin down what your DAC is and is not doing in actual use the way you have it hooked up.

It is nice this claimed DXD capable DAC you mention is so good that you're buying another DXD capable DAC. Talk about early adopters...not average audiophiles (oxymoron)...proves my point about the lack of genuine consumer demand for yet more formats, plural.

doak's picture
Submitted by doak on December 16, 2014 - 12:36pm

for your perusal:

http://audio-gd.com/Pro/dac/NFB32014/NFB32014EN.htm

corrective_unconscious's picture
Submitted by corrective_unco... on December 25, 2014 - 12:23pm

Unless verified independently.

The model number was right in the independent review I linked to.

And, again, despite all the excited claims, DXD is PCM. And many of these new DACs are converting the DSD to PCM to get it over a USB connection or to process it, anyway. That is, for those DSD files that weren't PCM somewhere along in the production process itself....

Something's fishy here in this whole DXD push, imo. Oh yeah, it's called "marketing."

Also, if you happen to be a manufacturer you should disclose that fact. I don't know how else you would know, or know to claim, that that review I linked to was of a different version of the DAC...which had the exact same model number....

Dr. AIX's picture
Submitted by Dr. AIX on December 15, 2014 - 1:37pm

DXD is a marketing term only and is not a recording or reproduction format! A site that offers DXD recordings is actually a PCM download site just like HDTracks, iTrax (my site) and others. It would be really helpful if the audio community would stop associating DSD and DXD...they are not similar.

As Jason rightly pointed out, DSD fails as a production format and requires PCM tools to edit, EQ, adjust levels, process with reverb etc. That's why high sample rate PCM (aka DXD) is required. And doing conversions back and forth do degrade the fidelity...so wouldn't it be better to stick with PCM in the first place?

Chose whatever sample rate and word size you want (96 kHz/24-bits are enough for me) but recognize that PCM is at the heart of virtually all recordings. 85% of all SACD were not recorded natively to DSD...they were either analog tape transfers or PCM.

Peter Scheelke's picture
Submitted by Peter Scheelke on December 16, 2014 - 1:42pm

Hey Guys

The name DXD (Digital eXtreme Definition) is justified by the definition of DXD: 352.8 kHz/24 bit in the converters and 352.8 kHz/32 or 64 bit floating point in the DAW.

In contrast to PCM DXD doesn't have a brick-wall filter in the AD converter. An aliasing filter is not necessary, as the analog amplitude at 150 kHz is lower than the noise floor of the AD converter.

An aliasing filter creates a pre/post ringing in the signal, and a steep filter has more ringing than a less steep filter. In our AX24 converter (Yes, I was co-founder of DAD) we only deployed a very soft filter from 130 kHz with minimal pre/post ringing.

Peter Scheelke

Dr. AIX's picture
Submitted by Dr. AIX on December 17, 2014 - 4:53pm

With all due respect, DXD is not a format. It may be an improvement on other PCM implementations...but it is most definitely PCM. The 352.8/24 "in the converters" and longer words in the DAW doesn't change anything. Longer words have been used in DAWS since I purchased my first Sonic Solution System in 1989.

The DXD marketing slogan should be acknowledged as high rate PCM and let's move on. Per- and Post ringing can be made virtually absent without moving to 352.8 kHz sampling rates.

Peter Scheelke's picture
Submitted by Peter Scheelke on December 19, 2014 - 3:01am

Music and sound consists of tones (frequencies) and clicks (pulses). While the lower sample rates reproduce the audible frequencies relatively well, they are less suitable for pulses. To reproduce the amplitude of a pulse high sample rates and very soft filters are needed. It is not possible digitally to recreate the energy of a pulse which once has been lost in a steep aliasing filter, in such a way that the filter does not affect the amplitude of the pulse.

A multibit system can always contain much more information than a single bit system with a similar bit rate. 24 bit PCM therefore has a dynamic range as high as 144 dB. There is no need to expand to 32 bits, since the dynamic range of 24 bits is far better than even the best AD converter.

Still DSD sounds better than 192 kHz/24 bit PCM, due to its amazing ability to reproduce a pulse. The theoretical pulse response of DSD is just over 100%. Unfortunately, DSD add a significant amount of noise to the signal. According to the original specification from Phillips, it is therefore necessary to add a low pass filter in the DA converter with a starting point at 50 kHz. This filter also attenuates the otherwise perfect pulse response, but the pulse response is still better than the pulse response of 192 Hz PCM.

It is indeed possible to create a better aliasing filter at 96 kHz and especially at 192 kHz sampling, where a softer filter with full attenuation around sf/2 as specified for PCM easily could be implemented.
Unfortunately, with very few exceptions no converter manufacturers have chosen to do so, because they don’t have the necessary insight. They are therefore stocked with the standard .45 -.55 filter which comes with the converter chip (a low pass filter which starts at 45% of the sample rate and has full attenuation at 55% of the sample rate).

DXD offers the best of both worlds. It is multibit, can therefore be edited and has the same noise performance as regular PCM. The sample rate is high enough to record all natural frequencies with amplitudes higher than the noise floor of the AD converter, and there is no aliasing filter to attenuate pulse response.

DXD is now the most widely used format for DSD editing, and the technically best way to produce a SACD is to record and edit in DXD and then convert to DSD only once.
Even the best sample rate converter has an impact on the sound, and it is an advantageous to minimize the amount of quantization noise from DSD.

We were all very fond of the name.

Peter Scheelke

Catcher10's picture
Submitted by Catcher10 on December 15, 2014 - 1:39pm

Not meant as a jab to those that listen to what is available on the Promates or NativeDSD, but there in lies the issue with these super high resolution music download files.

It is why I have not even looked into DSD, 24/96 or 24/192....There is almost nothing offered I listen to and I highly doubt it ever will be offered. Why spend four figure money for a DSD/DXD DAC to play nothing.

So sad...

Dr. AIX's picture
Submitted by Dr. AIX on December 18, 2014 - 2:12pm

I spent almost $50 with Promates...and it will be my last expenditure with them. The DXD. or as it should rightly be called high-rate PCM, file contains nothing but noise above 45 kHz! The sound of the PCM 88.2 kHz downconversion actually sounds better to my ears through my system. You can see the spectra at RealHD-Audio today.

This race to higher and higher sample rates is getting audio no where. Just make great recordings and 96 kHz/24-bit PCM is fine.

Peter Scheelke's picture
Submitted by Peter Scheelke on December 19, 2014 - 8:26am

I'm really glad you brought this up, since the answer to this question is indispensable for a proper understanding of DXD.

To gain full advantages of DXD a wide bandwidth is required in the entire audio system from the microphones to the speakers.

If the high frequencies are significantly attenuated in the analog path, unwanted distortion may occur. In such cases you are better off with a great down sampling.

I guess that you also like 88.2 kHz better than SACD’s. If your DA converter has a wide frequency response you could try to compare the sound between DXD and 88.2 kHz in headphones.

Carl Nielsen 1 and 4 are recorded in DXD with the best possible equipment. The down sampling to 88.2 kHz is then made with the best possible sample rate converter and optimized filters. 88.2 kHz cannot sound better than it does here.

If you send me a ticket from the music store, I will in return send you a link to a free download of Carl Nielsen's Symphony no. 2.

All the new recordings of Carl Nielsen symphonies are made by Preben Iwan, with the same microphones, in the same location, with the same orchestra. Of course there are minor differences in the microphone setup, but the major difference is that Symphony no. 2 is recorded at 96 kHz, with Millennia mic pre-amps and Prism AD converters using the typical.45 - .55 filter.

Since both Prism and Millennia are well known for their excellent equipment, it is interesting to know whether you think that there is a qualitative difference between the two recordings on your equipment.

Peter Scheelke

Dr. AIX's picture
Submitted by Dr. AIX on December 19, 2014 - 9:12am

Thanks Peter for the offer. As a recording engineer and high-resolution advocate, I understand the critical steps that a fine recording requires. The high-rate PCM version might sound different because of the amplitude differences between it and the high-resolution 88.2 kHz/24-bits. There isn't anything in the high-rate PCM version that isn't there in the 88.2 version except an additional 5 dB of overall amplitude.

If the conversion is done in the Pyramix system, why the difference?

Peter Scheelke's picture
Submitted by Peter Scheelke on December 19, 2014 - 3:06pm

It is correct that the sample rate conversion is done in Pyramix, however when I mount the first track of both formats in Pyramix their peak levels are exactly -1.7 dBfs for both files.

Why do you think there is a difference?

Peter Scheelke

Peter Scheelke's picture
Submitted by Peter Scheelke on December 19, 2014 - 4:07pm

As I did not understand your observations, I have listened to the 88.2 kHz and the DXD versions of Carl Nielsen 4 again. When listening to the files from Pyramix with my Horus DAC, there is absolutely no difference in the level. The sound of the DXD version is also much more clear and calm, with many more nuances, warmth and precision. These two versions are very different.

The only explanation I can think of is that your DAC is not playing the DXD version correctly.

Peter Scheelke

corrective_unconscious's picture
Submitted by corrective_unco... on December 20, 2014 - 1:53pm

Many of these DACs which are marketed as DSD or DXD compatible are just switching things to regular PCM somewhere along the line.

It's called, "marketing." It's not really called, "not playing the DXD version correctly."

John Atkinson's picture
Submitted by John Atkinson on December 20, 2014 - 5:08am
Dr. AIX wrote:
The DXD. or as it should rightly be called high-rate PCM, file contains nothing but noise above 45 kHz! . . . This race to higher and higher sample rates is getting audio no where. Just make great recordings and 96 kHz/24-bit PCM is fine.

According to Meridian's Bob Stuart, while the content of music above twice the audio baseband is indeed primarily low-level noise, capturing and reproducing that >44.1kHz content allows the system to reproduce the time-domain accurately and in a manner consonant with human hearing.

John Atkinson
Editor, Stereophile

ManWhoCan's picture
Submitted by ManWhoCan on September 12, 2018 - 4:13pm

@Jason,
Your comparison via your DAC of DSD and DXD is flawed! Your DAC can't give you real DSD. All DSD is converted to PCM in your DAC. Despite this I doubt your final conclusions would be any different.

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