Editing Direct Stream Digital

{{Short description|System for digitally encoding audio signals}}
{{Use mdy dates|date=January 2016}}
{{Essay-like|date=March 2014}}

{{Infobox storage medium
| name = Direct Stream Digital
| logo = [[File:DSDlogo.svg|class=skin-invert|140px|DSD logo]]
| image =
| caption =
| type = {{unbulleted list|Audio recording process|Disc format}}
| encoding = Digital
| capacity =
| read = DSD
| write = [[Super Audio CD]]
| standard = ISO/IEC 14496-3
| use = Audio recording
| extended from = 
| extended to = present
| released = 1999
}}

'''Direct Stream Digital''' ('''DSD''') is a [[trademark]] used by [[Sony]] and [[Philips]] for their system for digitally encoding audio signals for the [[Super Audio CD]] (SACD).

DSD uses [[delta-sigma modulation]], a form of [[pulse-density modulation]] encoding, a technique to represent audio signals in digital format, a sequence of [[Audio bit depth|single-bit]] values at a [[sampling rate]] of 2.8224&nbsp;[[megahertz|MHz]]. This is 64 times the [[CD audio]] sampling rate of [[44.1&nbsp;kHz]], but with 1-bit samples instead of 16-bit samples. [[Noise shaping]] of the 64-times [[oversampling|oversampled]] signal provides low [[Quantization (signal processing)|quantization]] noise and low [[distortion]] in the audible bandwidth necessary for [[high resolution audio]].

DSD is simply a format for storing a [[Delta-sigma modulation|delta-sigma]] signal without applying a [[decimation (signal processing)|decimation]] process that converts the signal to a [[Pulse-code modulation|PCM]] signal.

==Development==
DSD technology was developed and commercialized by Sony and Philips, the designers of the audio [[compact disc|CD]]. However, in 2005, Philips sold its DSD tool division to [[Sonic Studio]].<ref>{{cite web |url=http://www.highfidelityreview.com/sonic-studio-takes-over-philips-protech-dsd-i-sacd-products-hfr.html |title=Sonic Studio Takes Over Philips ProTech DSD i SACD Products [HFR] |date=July 9, 2005 |work=HighFidelityReviews |access-date=October 27, 2018}}</ref>{{better source needed|date=October 2018}}

;Major label support
[[DVD-Audio]] was endorsed by the Warner Music Group, while the SACD format was endorsed by [[Sony Music|Sony]] and [[Universal Music Group]], with an especially high-profile by UMG imprint [[Virgin Records]].<ref>{{cite interview|url=https://www.genesis-news.com/c-Genesis-SACDs-Nick-Davis-talks-to-it-about-the-new-51-mixes-s89.html|last=Davis|first=Nick|subject-link=Nick Davis (record producer)|interviewer=Christian Gerhardts|title=Genesis on SACD: Nick Davis interview|access-date=November 3, 2011}}</ref><ref>{{cite web |url=https://www.genesis-news.com/c-Genesis-Reviews-SACDs-c91.html |title=Genesis Reviews {{!}} SACD |access-date=October 27, 2018}}</ref> Despite this, in 2011, ''[[The Warner Premium Sound series]]'' of albums was released by [[Warner Music Group]], marking the first time the label released titles in a SACD format, with recording in DSD.<ref name="theseconddisc" >{{cite web|url=http://theseconddisc.com/2011/07/15/eagles-deep-purple-yes-out-of-print-dvd-audios-coming-to-sacd/|title=Eagles, Deep Purple, Yes! Out-Of-Print DVD-Audios Coming To SACD|access-date=November 3, 2011|first=Joe|last=Marchese|date=July 15, 2011|work=The Second Disc}}</ref> The series grew to ten [[Rock music|rock]] and [[Pop music|pop]] albums, with Super Audio CD/CD [[hybrid disc]]s containing both an SACD layer and a standard CD layer.<ref>{{cite web|url=https://www.mofi.com/category-s/1821.htm|title=Ultradisc UHR SACD|work=Mobile Fidelity|access-date=October 27, 2018|archive-date=October 28, 2018|archive-url=https://web.archive.org/web/20181028033741/https://www.mofi.com/category-s/1821.htm|url-status=dead}}</ref>

Sony did not promote SACD actively in North America, with the result that DVD-Audio gained competitive traction in the market. Elsewhere, such as in Europe or Japan, SACD gained more of a foothold.<ref>{{cite web|url=http://www.dvd-a.net/|work=DVD-A.net|access-date=October 27, 2018|title=March 30<!--not a typo, they do not title their posts-->|date=March 30, 2008|quote=In Europe and some other parts of the world this was done using the SACD format but not in North America, like with other reissues (such as the Depeche Mode albums).}}</ref> Examples include the German [[Stockfisch Records]], which releases [[vinyl record|vinyl]] editions of albums and DSD-recordings, released as hybrid SACDs.<ref>{{cite web|url=https://www.stockfisch-records.de/pages_art/sf12_dmmcd_e.html |title=A new format: The Stockfisch DMM-CD/SACD |work=[[Stockfisch Records]] |date=February 5, 2016 |access-date=October 27, 2018 }}</ref>

;Independent label use
Music companies that specialize in Super Audio CD products therefore use DSD encoding. A number of independent record labels have also worked directly with Sony to focus on DSD products or the DSD recording process.

[[DMP Digital Music Products]] was an early user of the SACD digital audio format.<ref>{{cite interview|url=http://www.stereophile.com/interviews/604jung/|date=June 27, 2004|title=Tom Jung of DMP: Making Musical Sense|work=Stereophile Magazine|first=Tom|last=Jung|interviewer=David Lander|access-date=October 27, 2018}}</ref> In 1997 their release ''Alto'' by [[Joe Beck]] & [[Ali Ryerson]] was the first commercial recording captured with Sony's DSD recording technology. The label's ''Just Jobim'' by [[Manfredo Fest]] in 1998 was the first project captured with the new Meitner DSD conversion technology. In 2000, DMP released the world's first multi-channel SACD—''Sacred Feast'' by Gaudeamus.<ref>{{cite web|url=https://www.discogs.com/Gaudeamus-Sacred-Feast/release/10213587 |title=Gaudeamus – Sacred Feast|work=Discogs|access-date=October 27, 2018}}</ref>

The majority of [[Telarc International Corporation]]'s releases were on (generally hybrid) SACD, and are DSD recordings.<ref>{{Cite web |url=http://www.telarc.com/ |title=Official site |access-date=January 6, 2015 |archive-url=https://web.archive.org/web/19980114070239/http://www.telarc.com/ |archive-date=January 14, 1998 |url-status=dead |df=mdy-all }}</ref>{{Failed verification|date=October 2018}} Telarc often worked with early audiophile company [[Soundstream]], and re-released many of its original Soundstream recordings in SACD format.<ref>{{citation|first=Jack|last=Renner|title=The Roots of Telarc|work=Telarc newsletter|date=Fall 1992}}</ref> Soundstream, which made the first [[digital recording]] in the United States, recorded in 16-bit PCM at a sample rate of 50&nbsp;kHz via its own proprietary digital recorder. This 50&nbsp;kHz PCM format was converted to DSD for release on Telarc SACD.

The record label [[Mobile Fidelity]] had engineers who decided to adopt the SACD over the DVD-Audio disc as a favored high-resolution digital format after listening tests and technical evaluations. On the label's Hybrid SACD releases, the SACD layer is a direct DSD recording of the analog master tape, while the CD layer is a digital down conversion of the DSD, with [[Super Bit Mapping]] applied. Post-2001, CD-only releases are sourced from DSD, but omit the SACD layer.<ref name="Enjoy the Music">{{cite web |url=http://www.enjoythemusic.com/news/1199/ |title=Enjoy the Music |access-date=November 12, 2010}}</ref>

In 2007, [[Blue Coast Records]] was founded in California for the purpose of recording and releasing music recorded with the DSD format, primarily focusing on [[jazz]] and acoustic artists.<ref name="mixonline">{{cite news
 |title=5.1 Recording Vibes With ESE 
 |author=Rick Clark 
 |url=http://mixonline.com/mag/audio_recording_vibes_ese/index.html 
 |newspaper=Mix 
 |date=May 1, 2004 
 |access-date=November 19, 2013 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20131203021355/http://mixonline.com/mag/audio_recording_vibes_ese/index.html 
 |archive-date=December 3, 2013 
 |df=mdy 
}}</ref>

On August 28, 2013, the [[Acoustic Sounds]] label launched SuperHiRez.com (now defunct), which sold mainstream albums from major record labels that were produced with Direct Stream Digital or PCM audio formats.<ref name="marketnews">{{cite news|archive-url=https://web.archive.org/web/20130904101041/http://www.marketnews.ca/LatestNewsHeadlines/AcousticSoundsLaunchesHi-ResDownloadService.html|url=http://www.marketnews.ca/LatestNewsHeadlines/AcousticSoundsLaunchesHi-ResDownloadService.html|first=Gordon|last=Brockhouse|title=Acoustic Sounds Launches Hi-Res Download Service|work=MarketNews|date=August 28, 2013|archive-date=September 4, 2013|url-status=dead|access-date=October 27, 2018}}</ref><ref>{{cite news |url=https://www.usatoday.com/story/tech/personal/2013/08/28/acoustic-sounds-high-resolution-music-downloads/2710783/ |first=Mike |last=Snider |title=Kansas firm raises bar on high-res music downloads |work=USA TODAY |date=August 28, 2013}}</ref> On September 4, 2013, Acoustic Sounds announced an agreement with [[Sony Music Entertainment]] to provide the company's new digital download service with albums that have been produced or remastered in DSD format.<ref>{{cite web|url=https://www.audiostream.com/content/acoustic-sounds-announces-deal-sony-music|first=Michael|last=Lavorgna|title=Acoustic Sounds Announces DSD Deal with Sony Music!|work=AudioStream|date=September 4, 2013|access-date=October 27, 2018}}</ref>

The format is used on albums such as ''[[Pop, Songs & Death]]'' in 2009,<ref>{{cite web |url=http://www.ps3sacd.com/news.html#_20090724 |title=Wheatus' new record downloadable in DSD |publisher=PS3SACD.com |date=July 24, 2009 |archive-url=https://web.archive.org/web/20180929020229/http://www.ps3sacd.com/news.html#_20090724 |archive-date=September 29, 2018 |access-date=October 27, 2018 |url-status=live |df=mdy-all }}</ref> and the remastered [[The Rolling Stones]] album ''Their Satanic Majesties Request'' in 2002.<ref name=Billboard>{{Cite news |url=https://www.billboard.com/articles/news/74557/the-rolling-stones-remastered-super-audio-cds |first=Christopher |last=Walsh |title=The Rolling Stones Remastered - Super Audio CDs |magazine=Billboard |page=27 |date=August 24, 2002}}</ref><ref name=Billboard2>{{cite news|url=https://www.billboard.com/articles/news/75597/rolling-stones-turn-to-super-audio-for-reissues|title=Rolling Stones Turn To 'Super Audio' For Reissues|date=May 30, 2002|magazine=Billboard|access-date=October 27, 2018}}</ref>

==DSD signal format==
[[File:PCM-vs-DSD.svg|thumb|Comparison with [[zero-order hold]] [[Pulse-code modulation|PCM]] ]]

DSD differs from the PCM format used by [[compact disc]] or typical computer audio systems: while PCM uses a multi-bit value (representing a large range of amplitudes) at a low sample rate, DSD instead uses a single-bit value (representing an increase or decrease in amplitude) at a sample rate much higher than the signal's [[Bandwidth (signal processing)|bandwidth]].

The process of creating a DSD signal is the same as the front-end modulator and noise-shaper portion of a [[Audio bit depth|1-bit]] [[delta-sigma modulation|delta-sigma]] [[analog-to-digital converter]] (ADC), without the back end [[Decimation (signal processing)|decimator]] (which would typically convert the 1-bit bitstream into multi-bit PCM). The short-term average of the 1-bit DSD [[bitstream]] signal is proportional to the original signal amplitude. Because of the higher sample rate, an SACD player can use a one-bit DAC with a low-order analog filter to [[Signal reconstruction|reconstruct]] and produce the analog output.

DSD uses [[noise shaping]] techniques to push [[quantization noise]] up to inaudible ultrasonic frequencies. Because of this, single rate DSD64 can deliver a [[dynamic range]] of 120&nbsp;[[decibel|dB]] from 20&nbsp;Hz to 20&nbsp;kHz and<!--Should this be ''or''? Opening the reconstruction filter and measurement bandwidth will bring in additional noise potentially lowering the dynamic range.--> an extended [[frequency response]] up to 100&nbsp;kHz (most recent SACD players specify an upper limit of 80 to 90&nbsp;kHz).{{citation needed|date=September 2023|reason=Many numbers of unknown origin in this paragraph}}

The various DSD formats use sampling rates well into the [[megahertz]] (MHz) range, typically with an ''oversampling ratio'' that is a [[power of two]] relative to the 44.1&nbsp;kHz rate used for CD audio:
{| class="wikitable"
|+
!Name
!Abbreviation
!Sample rate
!Oversampling ratio relative to 44.1&nbsp;kHz
!Notes
|-
|Single-rate DSD
|DSD64
|2.8224&nbsp;MHz
|64x
|The format used for SACD media.
|-
|Double-rate DSD
|DSD128
|5.6448&nbsp;MHz
|128x
|Since its establishment, content creators have made DSD128 recordings available, such as the audiophile label Opus3.<ref>{{cite web |author=Hiro |date=April 7, 2013 |title=Audiophile label Opus3 starts offering 5.6448MHz DSD downloads |url=https://puresuperaudio.blogspot.com/2013/04/audiophile-label-opus3-starts-offering.html |access-date=October 27, 2018 |work=Pure Super Audio}}</ref>
|-
|Quad-rate DSD
|DSD256
|11.2896&nbsp;MHz
|256x
|
|-
|Octuple-rate DSD
|DSD512
|22.5792&nbsp;MHz
|512x
|
|-
|Sexdecuple-rate DSD
|DSD1024
|45.1584&nbsp;MHz
|1024x
|
|}

See {{Slink|delta-sigma modulation|Theoretical effective number of bits}} for analysis of the [[effective number of bits]] that can be achieved by oversampling, especially when using a higher [[Order (differential equation)|order]] modulator.

==DSD mixing and mastering==
DSD music mixing and mastering for SACD or Internet download presents challenges due to the difficulty of performing digital signal processing (DSP) operations (such as equalization, balance, panning) in a one-bit environment.

Older analog recordings were processed using analog equipment and then digitized to DSD. It is also possible to avoid processing by using only the available adjustments in the studio equipment while recording to DSD.

One DSP technique available is to convert the DSD to PCM and use standard PCM equipment such as [[Pro Tools]], useful for rock and contemporary music which rely on multitrack techniques, then digitally convert back to DSD format. Some DSD proponents dislike this technique claiming that the PCM conversion to a lower sample rate reduces the sound quality of DSD.

A format and set of tools for PCM processing of DSD has been developed under the name [[Digital eXtreme Definition]] (DXD). This is a PCM format with 24-bit resolution sampled at 352.8&nbsp;kHz. Another DSP technique uses a format commonly referred to as ''DSD-wide'', which retains the high sample rate of standard DSD, but uses 8-bit samples with [[noise shaping]]. DSD-wide is sometimes disparagingly referred to as ''PCM-narrow''. It has the benefit of making DSP operations practical while retaining the 2.8224&nbsp;MHz sampling frequency. The processed DSD-wide signal is converted to the final 1-bit DSD product at the same sample rate. Processing DSD-wide at the higher multiple-DSD sample rates is also possible. Pyramix and some SADiE [[digital audio workstation]] (DAW) systems can operate in the DSD-wide domain.{{citation needed|date=December 2023}}

===DSD processing tools===
DXD was initially developed for the [[Merging Technologies]] Pyramix workstation and introduced together with their Sphynx 2, AD/DA converter in 2004. This combination meant that it was possible to record and edit directly in DXD,<ref>{{cite web|url=https://www.promates.com/music-store/hd-audio|title=Digital HD Audio Formats|access-date=October 27, 2014|archive-url=https://web.archive.org/web/20150621045338/https://www.promates.com/music-store/hd-audio|archive-date=June 21, 2015|url-status=dead|df=mdy-all}}</ref> and that the sample only converts to DSD once before publishing. This offers an advantage to the user as the noise created by converting DSD rises dramatically above 20&nbsp;kHz, and more noise is added each time a signal is converted back to DSD during editing.

The Pyramix Virtual Studio Digital Audio Workstation allows for recording, editing and mastering all DSD formats up to DSD256. A 12.288&nbsp;MHz DSD256 variant based on a 48&nbsp;kHz reference{{efn|{{times|48&nbsp;kHz|256}}&nbsp;{{=}} 12.288&nbsp;MHz as opposed to the more common {{times|44.1&nbsp;kHz|256}}&nbsp;{{=}} 11.2&nbsp;MHz}} is supported. The exaSound e20 DAC was the first commercially available device capable of DSD256 playback at sampling rates of 11.2896 or 12.288&nbsp;MHz.<ref>{{cite web|title=e20 Mk II - the first high-end DAC capable of DSD256|url=http://exasound.com/Blog/tabid/74/articleType/ArticleView/articleId/79/categoryId/8/e20-Mk-II--the-first-high-end-DAC-capable-of-DSD256.aspx}}</ref><ref>{{cite web|title=e20 Mk III - the first high-end DAC capable of 12.288 MHz (DSD256)|url=http://exasound.com/Blog/tabid/74/articleType/ArticleView/articleId/97/categoryId/8/e20-Mk-III--the-first-high-end-DAC-capable-of-12288-MHz-DSD256.aspx}}</ref> The Merging Technologies Horus AD/DA Converter offers sample rates up to 11.2&nbsp;MHz, or four times the SACD rate.

DSD128, 5.6448&nbsp;MHz, twice the SACD rate, has been supported by multiple hardware devices such as the exaSound e20 Mk II DA,C<ref>{{cite web|url= http://www.exasound.com/e20/Overview.aspx|title= exaSound e20 Mk II}}</ref> Korg MR-1000 1-bit digital recorder, Amanero Combo384 DSD output adapter and the discontinued exaU2I USB to [[I²S|I²S interface]]. 

Software supporting DSD includes [[Sonic Studio]]'s Amarra Luxe, Audirvana, [[foobar2000]] with SACD plugin, [[JRiver Media Center]], Roon,<ref>{{cite web|url=https://community.roonlabs.com/t/dsd512-upsampled-free-demo-from-www-wechdomi-org-resolved-with-build-218/24188/7|title=DSD512 ...upsampled free demo from www.wechdomi.org [Resolved with build 218]|date=April 17, 2017|quote=Thanks @wizardofoz, managed to download the 'Wechseldominante - Babel DSD512\Wechseldominante - Babel (DSD512).dff' and playback on my Holo Spring DAC. Direct DSD512 playback is far less computer intensive if it doesn't do any form of conversion. I managed to playback DSD512 without any issue.}}</ref> HQPlayer and Neutron Music Player are all able to handle DSD files of up to DSD512 rate fully natively.

==DSD playback options==
Sony developed DSD for SACD, and many disk players support SACD. Since the format is digital, there are other ways to play back a DSD stream; the development of these alternatives has enabled companies to offer high-quality [[music download]]s in DSD.<ref name="positivefeedback">{{cite web |url=http://www.positive-feedback.com/Issue60/dsd.htm |title=The Higher End: From an Editor's Notebook - Downloadable DSD |first=David W. |last=Robinson |date=April 2012 |publisher=Positive Feedback Online |access-date=May 14, 2012}}</ref>

===DSD disc format===
Some professional audio recorders (from [[Korg]], [[Tascam]], and others) can record in DSD format. Transferring this signal to a recordable DVD with the appropriate tools, such as the [[AudioGate]] software bundled with Korg MR-2000S recorder,<ref>[https://www.korg.com/us/products/drs/mr_2000s/ MR-2000S]</ref> renders a ''DSD Disc''. Such discs can be played back in native DSD only on certain Sony VAIO laptops and [[PlayStation 3]] systems.<ref>{{cite web |url=http://www.ps3sacd.com/faq.html#_Toc177216816 |title=PS3 SACD FAQ |publisher=PS3SACD.com |access-date=August 8, 2010 |archive-url=https://web.archive.org/web/20181019113937/http://www.ps3sacd.com/faq.html#_Toc177216816 |archive-date=October 19, 2018}}</ref> Sony produced two SACD players, the SCD-XA5400ES and the SCD-XE800, that fully support the DSD-disc format. In June 2012, [[Pioneer Corporation|Pioneer]] launched a series of SACD players compatible with DSD-disc. The PD-30 and PD-50. In January 2013, [[TEAC Corporation|TEAC]] announced a DSD-disc compatible player, the PD-501HR.<ref>{{cite web|url=http://www.whathifi.com/news/ces-2013-teac-announces-reference-501-the-most-advanced-mini-hi-fi-system-in-the-world|title=CES 2013 Announcement|date=January 8, 2013 }}</ref>

===DSD over USB===
An alternative to burning DSD files onto disks for eventual playback is to transfer the (non-encrypted) files from a computer to audio hardware over a digital link such as USB. The [[USB audio]] 2.0 specification defined several formats for the more common PCM approach to digital audio, but did not define a format for DSD.

In 2012, representatives from many companies and others developed a standard to represent and detect DSD audio within PCM frames; the standard, commonly known as DSD over PCM (DoP), is suitable for other digital links that use PCM.<ref name="DoP open Standard">{{cite web |url=http://dsd-guide.com/usb-link-dsd-audio-pcm-frames-andreas-koch |title=Method for transferring DSD Audio over PCM Frames Version 1.1 |first=Andreas |last=Koch |date=March 30, 2012 |publisher=DSD-Guide.com |archive-url=https://web.archive.org/web/20120515083952/http://dsd-guide.com/usb-link-dsd-audio-pcm-frames-andreas-koch |archive-date=May 15, 2012 |access-date=May 14, 2012 |display-authors=etal |url-status=dead |df=mdy }}</ref> The 1.1 revision added protocol support for higher DSD sample rates without requiring an increase the underlying PCM sample rate.

===Native DSD===
The definition of ''native DSD'' playback is somewhat a matter of philosophy. Generally speaking, it avoids the conversion of DSD data into multibit PCM anywhere along the reproduction chain.{{citation needed|date=January 2022}} Many commercially available DACs now support ''native DSD''.

==DSD vs. PCM==
There has been much controversy between proponents of DSD and PCM over which encoding system is superior. In 2000, Lipshitz and Vanderkooy stated that one-bit converters, as employed by DSD, are unsuitable for high-end applications due to their high distortion.<ref>{{Cite web |last=Lipschitz |first=Stanley P. |last2=Vanderkooy |first2=John |date=2000-09-22 |title=Why Professional 1-Bit Sigma-Delta Conversion is a Bad Idea |url=http://peufeu.free.fr/audio/extremist_dac/files/1-Bit-Is-Bad.pdf |url-status=dead |archive-url=https://web.archive.org/web/20221102075257/http://peufeu.free.fr/audio/extremist_dac/files/1-Bit-Is-Bad.pdf |archive-date=2022-11-02}}</ref><ref>{{Cite web |last=Lipshitz |first=Stanley P. |last2=Vanderkooy |first2=John |date=2001-05-12 |title=Why 1-Bit Sigma-Delta Conversion is Unsuitable for High-Quality Applications |url=https://sjeng.org/ftp/SACD.pdf |url-status=live |archive-url=https://web.archive.org/web/20230430093353/https://sjeng.org/ftp/SACD.pdf |archive-date=2023-04-30 |access-date=2023-08-28}}</ref> In 2002, Philips published a paper arguing the contrary.<ref>{{cite web |title=Enhanced Sigma Delta Structures for Super Audio CD Applications |url=https://aes2.org/publications/elibrary-page/?id=11395 |first=Derk |last=Reefman |first2=Erwin |last2=Janssen |publisher=Audio Engineering Society |access-date=23 October 2024 |date=6 April 2002 |language=English}}</ref> Lipshitz and Vanderkooy's paper was further criticized by Angus.<ref>[https://www.aes.org/member/profile.cfm?ID=858226096 Angus-Whiteoak, Jamie A S]. <!-- https://www.semanticscholar.org/paper/The-Effect-of-Idle-Tone-Structure-on-Effective-in-Angus/1c322500e19e019ae747b7998c25f1f45e946b39 -->[https://www.aes.org/e-lib/browse.cfm?elib=11303 "The Effect of Idle Tone Structure on Effective Dither in Delta-Sigma Modulation Systems"], {{cite web |title=Session X: SIGNAL PROCESSING FORUM - PART 1 |url=https://www.aes.org/events/112/papers/x.cfm <!-- |website=AES 112th Convention --> }} [[Audio Engineering Society]] 112th Convention, Munich, April, 2002, [https://web.archive.org/web/20060823173606/http://www.acoustics.salford.ac.uk/research/angus_files/angus_files/publications/publications.htmpreprint #5619].  [http://www.salford.ac.uk/computing-science-engineering/cse-academics/jamie-angus (Professor of Audio Technology)] 
[https://web.archive.org/web/20040404135257/http://www.acoustics.salford.ac.uk/research/angus_files/arc_angus1.htm Professor James Angus BSc, PhD (Kent), FIOA, MAES] [https://web.archive.org/web/20040224193651/http://www.acoustics.salford.ac.uk/research/angus_files/angus_files/publications/publications.htm Publications] [https://web.archive.org/web/20070805025908/http://www.acoustics.salford.ac.uk/res/angus/index.php Research Projects]</ref> Lipshitz and Vanderkooy responded to the criticisms.<ref>{{cite web |last1=Vanderkooy |first1=John |last2=Lipshitz |first2=Stanley P. |title=Towards a Better Understanding of 1-Bit Sigma-Delta Modulators - Part 3 |url=https://www.aes.org/e-lib/browse.cfm?elib=11342 |publisher=Audio Engineering Society |access-date=23 January 2021 |language=English |date=1 April 2002}} {{cite web |title=Session X: SIGNAL PROCESSING FORUM - PART 1 |url=https://www.aes.org/events/112/papers/x.cfm |website=[[Audio Engineering Society]] 112th Convention, Munich, April, 2002 }}.</ref> Stuart also defined [[sigma-delta modulation]] a "totally unsuitable choice" for high-resolution digital audio.<ref>{{cite journal|url=http://www.ece.rochester.edu/courses/ECE472/Site/Assignments/Entries/2009/1/15_Week_1_files/Stuart_2004.pdf|title=Coding for High-Resolution Audio Systems|first=J. Robert|last=Stuart|s2cid=18072620|journal=J. Audio Eng. Soc.|volume=52|issue=3|date=March 2004|pages=139–142|access-date=January 24, 2021|archive-date=February 7, 2021|archive-url=https://web.archive.org/web/20210207174138/http://www2.ece.rochester.edu/courses/ECE472/Site/Assignments/Entries/2009/1/15_Week_1_files/Stuart_2004.pdf|url-status=dead}}</ref>

Conventional implementation of DSD has an intrinsic high distortion.<ref>{{cite journal|last=Hawksford|first=M.|year=2001|url=http://www.essex.ac.uk/ESE/research/audio_lab/malcolmspubdocs/C115%20SDM%20versus%20LPCM.pdf|title=SDM versus LPCM: The Debate Continues|archive-url=https://web.archive.org/web/20060513223001/http://www.essex.ac.uk/ESE/research/audio_lab/malcolmspubdocs/C115%20SDM%20versus%20LPCM.pdf |archive-date=May 13, 2006|journal=AES Convention|page=5397}}</ref> Distortion can be alleviated to some degree by using multibit DACs. State-of-the-art ADCs are based around sigma-delta modulation designs. Oversampling converters are usually used in linear PCM formats, where the ADC or DAC output is subject to bandlimiting and dithering.<ref>(Hawksford 1995).</ref> Most modern ADC and DAC converters use oversampling and a multi-bit design; in other words, while DSD is a 1-bit format, modern converters internally use a 2-bit<ref>See the AK5381 ADC datasheet</ref> to 6-bit<ref>See the PCM4222 data sheet</ref> format.

Comparisons of DSD and PCM recordings with the same origin, number of channels and similar bandwidth and noise have yielded contradictory results. A 2004 study conducted at the Erich-Thienhaus Institute in Detmold, Germany found that in [[blind test|double-blind tests]] "hardly any of the subjects could make a reproducible distinction between the two encoding systems."<ref>{{cite journal|title=DVD-Audio versus SACD: Perceptual Discrimination of Digital Audio Coding Formats|last1=Blech|first1=Dominic|last2=Yang|first2=Min-Chi|journal=Erich-Thienhaus-Institute (Tonmeisterinstitut)|location=University of Music Detmold, Germany|year=2004|url=http://www.hfm-detmold.de/eti/projekte/diplomarbeiten/dsdvspcm/aes_paper_6086.pdf |access-date=July 27, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20070927200955/http://www.hfm-detmold.de/eti/projekte/diplomarbeiten/dsdvspcm/aes_paper_6086.pdf |archive-date=September 27, 2007 |df=mdy }}</ref> In contrast, a 2014 study conducted at the [[Tokyo University of the Arts]] found that listeners could distinguish PCM (192&nbsp;kHz/24&nbsp;bits) from either DSD (2.8&nbsp;MHz) or DSD (5.6&nbsp;MHz) (but not between the two DSD samplings), preferring the sound of DSD over PCM: "For example, Drums stimulus of DSD (5.6&nbsp;MHz) has p&nbsp;=&nbsp;0.001 when compared against PCM (192&nbsp;kHz/24&nbsp;bit) in overall preference. This suggests that DSD version was statistically significantly preferred over the PCM version."<ref>Marui, A., Kamekawa, T., Endo, K. and Sato, E., 2014, April. Subjective evaluation of high resolution recordings in PCM and DSD audio formats. In Audio Engineering Society Convention 136. Audio Engineering Society.</ref> These findings are questionable however, because "the two formats were subject to different processing, most notably, different filtering of the low-frequency content."<ref>Reiss, J.D., 2016. A meta-analysis of high resolution audio perceptual evaluation. Journal of the Audio Engineering Society, 64(6), pp.364-379.</ref>

Even though DSD-based SACD was more successful than its direct competitor, the PCM-based DVD-Audio, DSD met with relatively little success in the consumer market. Direct manipulation of recorded DSD data is difficult due to the limited availability of appropriate software. The advent of new high-resolution PCM standards, such as [[Digital eXtreme Definition|DXD]], further restricted DSD's market niche.

==DSD file formats==
There are several ways to store DSD encoded audio as files on a computer. One option is to use DSD native file formats used specifically for this purpose. Alternatively, DSD can be stored in general purpose audio formats officially adapted to support DSD storage. Finally, DSD audio can be embedded into PCM audio streams that do not have special DSD support. However, a special decoder is needed to recover the DSD stream from these PCM files.

===DSD Interchange File Format===
{{Infobox file format
| name          = DSD Interchange File Format
| extension     = .dff
| mime          = audio/x-dff
| owner         = [[Philips]]
| type          = DSD Audio
| latest_release_version = 1.5
| latest_release_date = 2004-27-04
| url           = sonicstudio.com/pdf/dsd/DSDIFF_1.5_Spec.pdf
}}

''DSD Interchange File Format'' (DSDIFF) is a native DSD file format developed by [[Philips]] between 2000 and 2004 for storage of DSD recordings.<ref>{{Citation
| year        = 2004
| title       = Direct Stream Digital Interchange File Format
| publisher   = Royal Philips Electronics
| url         = https://dsd-guide.com/sites/default/files/white-papers/DSDIFF_1.5_Spec.pdf
| access-date = 2022-07-15
}}</ref> The format supports [[DST compression]] of the payload as well as annotations used in Super Audio CD production. A single DSDIFF file may store an entire album as a single audio stream together with markers indicating the location of individual tracks for the album. Some parts of the audio content may be left out entirely from the resulting SACD. The embedded metadata format is intended for mastering engineers not consumers. For example, markers indicating the beginning of a new audio track have a text field for storing arbitrary text-based information. However, there is no requirement for the text to contain the title of the track. A [[de facto standard]] for including [[ID3]] metadata in an unofficial ID3 chunk was later developed as consumers adopted the format for storing individual tracks of DSD audio. DSDIFF files typically use the <code>.dff</code> file suffix. No official [[media type]] has been registered for the DSDIFF file format.<ref name="Media Types">{{Citation
| year        = 2022
| title       = Media Types
| publisher   = IANA
| url         = https://www.iana.org/assignments/media-types/media-types.xhtml
| access-date = 2022-07-15
}}</ref> [[Freedesktop.org]] uses the unofficial media types <code>audio/x-dff</code>.<ref name=":0">{{Citation
| year        = 2022
| title       = Freedesktop.org Shared MIME Database
| publisher   = Freedesktop.org
| url         = https://cgit.freedesktop.org/xdg/shared-mime-info/tree/data/freedesktop.org.xml.in
| access-date = 2022-07-15
}}</ref>

===Wideband Single-bit Data===
{{Infobox file format
| name = Wideband Single-bit Data
| extension = .wsd
| mime =
| owner = [[1-bit Audio Consortium]]
| type = DSD Audio
}}

''Wideband Single-bit Data'' (WSD) is a native DSD file format developed by [[1-bit Audio Consortium]] in 2002.<ref>{{Citation
| year        = 2002
| title       = Specifications for 1-bit-coding Data File, version 1.0
| language    = ja
| publisher   = 1-bit Audio Consortium
| url         = http://www.acoust.rise.waseda.ac.jp/1bitcons/data2/020917wsd.pdf
| archive-url = https://web.archive.org/web/20031011125251fw_/http://www.acoust.rise.waseda.ac.jp/1bitcons/data2/020917wsd.pdf
| archive-date = 2003-10-11
}}</ref> The consortium was established by [[Waseda University]], [[Sharp Corporation|Sharp]] and [[Pioneer Corporation|Pioneer]] a year earlier.<ref>{{Citation
| year        = 2001
| title       = Waseda University, Sharp, and Pioneer Establish 1-bit Audio Consortium to Promote Next-Generation Audio Technology
| publisher   = Pioneer
| url         = https://global.pioneer/en/corp/news/press/index/1453
}}</ref> In 2012 the consortium published an updated 1.1 version of the specification.<ref>{{Citation
| year        = 2012
| title       = Specifications for 1-bit-coding Data File, version 1.1
| language    = ja
| publisher   = 1-bit Audio Consortium
| url         = http://1bitcons.acoust.ias.sci.waseda.ac.jp/pdf/wsd_file_format_ver1_1.pdf
| access-date = 2022-09-11
}}</ref> The WSD header has a field for storing an absolute timestamp in samples since midnight. The timestamp makes it possible to accurately know how much time passed between two recordings made consecutively on the same physical recording device. [[Korg]] portable recorders [[Korg MR-1|MR-1]], [[Korg MR-2|MR-2]], [[Korg MR-1000|MR-1000]] and [[Korg MR-2000s|MR-2000s]] support WSD alongside other DSD based formats.<ref>{{Citation
| date        = March 2007
| title       = Korg MR1000 & MR1 — High-resolution DSD Master Recorders
| first       = Hugh
| last        = Robjohns
| publisher   = [[Sound on Sound]]
| url         = https://www.soundonsound.com/reviews/korg-mr1000-mr1
| access-date = 2022-10-16
}}</ref><ref>{{Citation
| date        = 2010-12-21
| title       = KORG MR-2 recorder
| first       = Jez riley
| last        = French
| url         = http://jezrileyfrench-aquietposition.blogspot.com/2010/10/korg-mr-2-recorder-ive-just-received.html
| access-date = 2022-10-16
}}</ref><ref>{{Citation
| date        = 2009-01-08
| title       = Korg MR-2000S 1-Bit Studio Recorder Review
| first       = Barry
| last        = Rudolph
| publisher   = [[Mix (magazine)|Mix]]
| url         = https://www.mixonline.com/technology/korg-mr-2000s-1-bit-studio-recorder-review-369470
| access-date = 2022-10-16
}}</ref>

===DSD Stream File===
{{Infobox file format
| name          = DSD Stream File
| extension     = .dsf
| mime          = audio/x-dsf
| owner         = [[Sony]]
| type          = DSD Audio
| latest_release_version = 1.01
| latest_release_date = November 2005
| url           = dsd-guide.com/sonys-dsf-file-format-spec
}}

''DSD Stream File'' (DSF) is a native DSD file format developed by [[Sony]] around 2005.<ref>{{Citation
| year         = 2006
| title        = DSD Format License Agreement
| publisher    = Sony Corporation
| url          = http://www.dsd-format.sony.net:80/en/index.php
| archive-url  = https://web.archive.org/web/20060417193238/http://www.dsd-format.sony.net:80/en/index.php
| archive-date = 2006-04-17
}}</ref><ref>{{Citation
| year        = 2005
| title       = DSF File Format Specification
| publisher   = Sony Corporation
| url         = https://dsd-guide.com/sites/default/files/white-papers/DSFFileFormatSpec_E.pdf
| access-date = 2022-07-15
}}</ref> The format is intended for storing individual tracks of DSD audio and has native support for ID3 metadata inclusion. The format defines a "format ID" field that could presumably be used to indicate DST compression. However, the only identifier defined in the spec is number 0 indicating "DSD raw". Files containing DSF data would typically use the<code>.dsf</code> file suffix. No official media type has been registered for the DSF file format.<ref name="Media Types"/> Freedesktop.org uses the unofficial media types <code>audio/x-dsf</code>.<ref name=":0" />

===DSD compatible file formats===
DSD-compatible file formats support storing DSD-encoded audio in addition to audio encoded as [[PCM]].

[[WavPack]] is a generic audio storage format supporting various different forms of audio.<ref>{{Citation
| year        = 2020
| title       = WavPack 4 & 5 Binary File / Block Format
| last1        = Bryant
| first1       = David
| url         = https://www.wavpack.com/WavPack5FileFormat.pdf
| access-date = 2022-08-14
}}</ref> Compressed DSD audio is also supported by the format.<ref>{{Citation
| year        = 2022
| title       = Compressing DSD files with Wavpack 5
| publisher   = DIY Audio Heaven
| url         = https://diyaudioheaven.wordpress.com/digital/pc-software/compressing-dsd-files-with-wavpack-5/
| access-date = 2022-08-14
}}</ref> The DSD support was initially introduced with the release of WavPack software suite version 5 in December 2016.<ref>{{Citation
| year        = 2022
| title       = changelog.txt
| publisher   = wavpack.com
| url         = https://www.wavpack.com/changelog.txt
| access-date = 2022-09-06
}}</ref> Files containing WavPack data would typically use the<code>.wv</code> file suffix. No official media type has been registered for the WavPack file format.<ref name="Media Types"/> Freedesktop.org uses the unofficial media types <code>audio/x-wavpack</code>.<ref name=":0"/> Since WavPack supports multiple formats, the suffix or mime type alone does not indicate the presence of DSD audio.

===DSD over PCM (DoP)===

In addition to actual DSD file formats, a format called ''DSD Audio over PCM Frames'' (DoP) is used for embedding DSD into PCM audio streams.<ref>{{Citation
| year        = 2012
| title       = DoP Open Standard
| last1        = Koch
| first1       = Andreas
| last2        = McHarg
| first2       = Andy
| last3        = Rankin
| first3       = Gordon
| last4        = Jurewicz
| first4       = Michal
| url         = https://dsd-guide.com/sites/default/files/white-papers/DoP_openStandard_1v1.pdf
| access-date = 2022-07-15
}}</ref> DoP makes it possible to circumvent any PCM-only component in the playback chain that would prevent a DSD-capable DAC from receiving the raw DSD data required for native DSD playback. While DoP is intended to be a wire protocol used for communication between music player application and a DAC, there exists tools that can embed DoP-encoded DSD into FLAC files enabling users to use a non-DSD capable player for DSD playback with their DoP-capable DAC.<ref>{{Citation
| title       = Sonore dsd2flac
| publisher   = Simple Design, LLC
| url         = https://www.sonore.us/dsd2flac.html
| access-date = 2022-07-15
}}</ref> A DoP stream is designed to sound like low-volume noise when played back by a PCM-only DAC, while a DoP-capable DAC will detect the presence of DSD data, extract it from the PCM and play it back as DSD.

==See also==
* [[Audio bit depth]]
* [[Glossary of digital audio]]
* [[Super Bit Mapping]] (SBM)
* [[Timeline of audio formats]]

==Notes==
{{notelist}}

==References==
{{reflist}}

==Further reading==
* {{cite conference |url=https://aes2.org/publications/elibrary-page/?id=9902 |title=Why Direct Stream Digital is the best choice as a digital audio format}}
* {{cite conference |url=https://aes2.org/publications/elibrary-page/?id=11395 |title=Enhanced Sigma Delta Structures for Super Audio CD Applications}}
* {{cite conference |url=https://aes2.org/publications/elibrary-page/?id=11303 |title=The Effect of Idle Tone Structure on Effective Dither in Delta-Sigma Modulation Systems}}

==External links==
*{{cite web|url=http://www.smr-home-theatre.org/surround2002/technology/page_07.shtml |title=Poking a Round Hole in a Square Wave |access-date=2006-08-05 |url-status=deviated |archive-url=https://web.archive.org/web/20071011014242/http://www.smr-home-theatre.org/surround2002/technology/page_07.shtml |archive-date=October 11, 2007 |df=mdy }} —DSD vs PCM comparison
* {{web archive |url=https://web.archive.org/web/20080901162000/http://www.dsd-format.sony.net/en/index.php |title=DSF and DSD Disc Format specifications}}, by Sony
* [http://www.ps3sacd.com/dsddiscguide.html How to make a DSD Disc using a Korg DSD Recorder] including DSD plug-in for [[Windows Media Player]]
* {{web archive |url=https://web.archive.org/web/20170720120659/http://www.rigisystems.net/index.php/usbpalen.html |title=Low latency Multi-channel USB 2.0 Audio}}, DSD recording playback over [[USB]] software and hardware development kit
* [http://www.ps3sacd.com/dsd_downloads.html DSD downloads]

{{Audio formats}}
{{Sony}}

[[Category:Audiovisual introductions in 1999]]
[[Category:Audio codecs]]
[[Category:Audio storage]]
[[Category:Digital audio storage]]