Direct Stream Digital (DSD) is a

trademark A trademark (also written trade mark or trade-mark) is a form of intellectual property that consists of a word, phrase, symbol, design, or a combination that identifies a Good (economics and accounting), product or Service (economics), service f ...

used by

Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...

and

Philips Koninklijke Philips N.V. (), simply branded Philips, is a Dutch multinational health technology company that was founded in Eindhoven in 1891. Since 1997, its world headquarters have been situated in Amsterdam, though the Benelux headquarter ...

for their system for digitally encoding audio signals for the

Super Audio CD Super Audio CD (SACD) is an optical disc format for audio storage introduced in 1999. It was developed jointly by Sony and Philips Electronics and intended to be the successor to the compact disc (CD) format. The SACD format allows multiple a ...

(SACD). DSD uses delta-sigma modulation, a form of

pulse-density modulation Pulse-density modulation (PDM) is a form of modulation used to represent an analog signal with a binary signal. In a PDM signal, specific amplitude values are not encoded into codewords of pulses of different weight as they would be in pulse ...

encoding, a technique to represent audio signals in digital format, a sequence of single-bit values at a

sampling rate In signal processing, sampling is the reduction of a continuous-time signal to a discrete-time signal. A common example is the conversion of a sound wave to a sequence of "samples". A sample is a value of the signal at a point in time and/or s ...

of 2.8224

MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base u ...

. This is 64 times the

CD audio Compact Disc Digital Audio (CDDA or CD-DA), also known as Digital Audio Compact Disc or simply as Audio CD, is the standard format for audio compact discs. The standard is defined in the '' Red Book'' technical specifications, which is why t ...

sampling rate of 44.1 kHz, but with 1-bit samples instead of 16-bit samples.

Noise shaping Noise shaping is a technique typically used in digital audio, Image processing, image, and video processing, usually in combination with dithering, as part of the process of Quantization (signal processing), quantization or Audio bit depth, bit-dep ...

of the 64-times oversampled signal provides low quantization noise and low

distortion In signal processing, distortion is the alteration of the original shape (or other characteristic) of a signal. In communications and electronics it means the alteration of the waveform of an information-bearing signal, such as an audio signal ...

in the audible bandwidth necessary for high resolution audio. DSD is simply a format for storing a delta-sigma signal without applying a decimation process that converts the signal to a

PCM Pulse-code modulation (PCM) is a method used to Digital signal (signal processing), digitally represent analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio application ...

signal.

Development

DSD technology was developed and commercialized by Sony and Philips, the designers of the audio CD. However, in 2005, Philips sold its DSD tool division to Sonic Studio. ;Major label support

DVD-Audio DVD-Audio (commonly abbreviated as DVD-A) is a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio uses most of the storage on the disc for high-quality audio and is not intended to be a video delivery format. The ...

was endorsed by the Warner Music Group, while the SACD format was endorsed by

and

Universal Music Group Universal Music Group N.V. (often abbreviated as UMG and referred to as Universal Music Group or Universal Music) is a Netherlands, Dutch–United States, American multinational Music industry, music corporation under Law of the Netherlands, ...

, with an especially high-profile by UMG imprint

Virgin Records Virgin Records is a British record label owned by Universal Music Group. They were originally founded as a British independent record label in 1972 by entrepreneurs Richard Branson, Simon Draper, Nik Powell, and musician Tom Newman (musician), ...

. Despite this, in 2011, '' The Warner Premium Sound series'' of albums was released by

Warner Music Group Warner Music Group Corp., commonly abbreviated as WMG, is an American Multinational corporation, multinational entertainment and record label Conglomerate (company), conglomerate headquartered in New York City. It is one of the "Record label#M ...

, marking the first time the label released titles in a SACD format, with recording in DSD. The series grew to ten rock and pop albums, with Super Audio CD/CD hybrid discs containing both an SACD layer and a standard CD layer. 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. Examples include the German Stockfisch Records, which releases

vinyl Vinyl may refer to: Chemistry * Polyvinyl chloride (PVC), a particular vinyl polymer * Vinyl cation, a type of carbocation * Vinyl group, a broad class of organic molecules in chemistry * Vinyl polymer, a group of polymers derived from vinyl ...

editions of albums and DSD-recordings, released as hybrid SACDs. ;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. In 1997 their release ''Alto'' by

Joe Beck Joe Beck (July 29, 1945 – July 22, 2008) was an American jazz guitarist who was active for over 40 years. Biography Born in Philadelphia, Beck moved to Manhattan in his teens, playing six nights a week in a trio setting, which gave him an opp ...

& 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. The majority of Telarc International Corporation's releases were on (generally hybrid) SACD, and are DSD recordings. Telarc often worked with early audiophile company Soundstream, and re-released many of its original Soundstream recordings in SACD format. Soundstream, which made the first

digital recording In digital recording, an audio signal, audio or video signal is converted into a stream of discrete numbers representing the changes over time in air pressure for audio, or Color, chroma and luminance values for video. This number stream is s ...

in the United States, recorded in 16-bit PCM at a sample rate of 50 kHz via its own proprietary digital recorder. This 50 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. 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 Jazz is a music genre that originated in the African-American communities of New Orleans, Louisiana, in the late 19th and early 20th centuries. Its roots are in blues, ragtime, European harmony, African rhythmic rituals, spirituals, h ...

and acoustic artists. 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. On September 4, 2013, Acoustic Sounds announced an agreement with

Sony Music Entertainment Sony Music Entertainment (SME), commonly known as Sony Music, is an American multinational music company owned by Japanese conglomerate Sony Group Corporation. It is the recording division of Sony Music Group, with the other half being the ...

to provide the company's new digital download service with albums that have been produced or remastered in DSD format. The format is used on albums such as '' Pop, Songs & Death'' in 2009, and the remastered

The Rolling Stones The Rolling Stones are an English Rock music, rock band formed in London in 1962. Active for over six decades, they are one of the most popular, influential, and enduring bands of the Album era, rock era. In the early 1960s, the band pione ...

album ''Their Satanic Majesties Request'' in 2002.

DSD signal format

DSD differs from the PCM format used by

compact disc The compact disc (CD) is a Digital media, digital optical disc data storage format co-developed by Philips and Sony to store and play digital audio recordings. It employs the Compact Disc Digital Audio (CD-DA) standard and was capable of hol ...

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. The process of creating a DSD signal is the same as the front-end modulator and noise-shaper portion of a 1-bit delta-sigma

analog-to-digital converter In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a Digital signal (signal processing), digi ...

(ADC), without the back end decimator (which would typically convert the 1-bit bitstream into multi-bit PCM). The short-term average of the 1-bit DSD

bitstream A bitstream (or bit stream), also known as binary sequence, is a sequence of bits. A bytestream is a sequence of bytes. Typically, each byte is an 8-bit quantity, and so the term octet stream is sometimes used interchangeably. An octet may ...

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 reconstruct and produce the analog output. DSD uses

noise shaping Noise shaping is a technique typically used in digital audio, Image processing, image, and video processing, usually in combination with dithering, as part of the process of Quantization (signal processing), quantization or Audio bit depth, bit-dep ...

techniques to push

quantization noise Quantization, in mathematics and digital signal processing, is the process of mapping input values from a large set (often a continuous set) to output values in a (countable) smaller set, often with a finite number of elements. Rounding and t ...

up to inaudible ultrasonic frequencies. Because of this, single rate DSD64 can deliver a

dynamic range Dynamics (from Greek δυναμικός ''dynamikos'' "powerful", from δύναμις ''dynamis'' " power") or dynamic may refer to: Physics and engineering * Dynamics (mechanics), the study of forces and their effect on motion Brands and ent ...

of 120 dB from 20 Hz to 20 kHz and an extended

frequency response In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and Phase (waves), phase of the output as a function of input frequency. The frequency response is widely used in the design and ...

up to 100 kHz (most recent SACD players specify an upper limit of 80 to 90 kHz). The various DSD formats use sampling rates well into the

megahertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base ...

(MHz) range, typically with an ''oversampling ratio'' that is a

power of two A power of two is a number of the form where is an integer, that is, the result of exponentiation with number 2, two as the Base (exponentiation), base and integer as the exponent. In the fast-growing hierarchy, is exactly equal to f_1^ ...

relative to the 44.1 kHz rate used for CD audio: See for analysis of the effective number of bits that can be achieved by oversampling, especially when using a higher 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 Pro Tools is a digital audio workstation (DAW) developed and released by Avid Technology (formerly Digidesign) for Microsoft Windows and macOS. It is used for music creation and production, sound for picture (sound design, audio post-productio ...

, 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 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

. DSD-wide is sometimes disparagingly referred to as ''PCM-narrow''. It has the benefit of making DSP operations practical while retaining the 2.8224 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 A digital audio workstation (DAW ) is an electronic device or application software used for Sound recording and reproduction, recording, editing and producing audio files. DAWs come in a wide variety of configurations from a single software pr ...

(DAW) systems can operate in the DSD-wide domain.

DSD processing tools

DXD was initially developed for the

Merging Technologies Merging Technologies is a Swiss manufacturer of professional audio Electronic hardware, hardware and software. History Merging Technologies was founded in 1990 in Puidoux, Vaud, by École Polytechnique Fédérale de Lausanne, EPFL electrical eng ...

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, 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 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 MHz DSD256 variant based on a 48 kHz reference 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 MHz. The Merging Technologies Horus AD/DA Converter offers sample rates up to 11.2 MHz, or four times the SACD rate. DSD128, 5.6448 MHz, twice the SACD rate, has been supported by multiple hardware devices such as the exaSound e20 Mk II DA,C Korg MR-1000 1-bit digital recorder, Amanero Combo384 DSD output adapter and the discontinued exaU2I USB to I²S interface. Software supporting DSD includes Sonic Studio's Amarra Luxe, Audirvana, foobar2000 with SACD plugin, JRiver Media Center, Roon, 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 A music download is the digital transfer of music via the Internet into a device capable of decoding and playing it, such as a personal computer, portable media player, MP3 player or smartphone. This term encompasses both legal downloads ...

s in DSD.

DSD disc format

Some professional audio recorders (from

Korg , founded as Keio Electronic Laboratories, is a Japanese multinational corporation that manufactures electronic musical instrument An electronic musical instrument or electrophone is a musical instrument that produces sound using electr ...

Tascam TASCAM is the professional audio division of TEAC Corporation, headquartered in Tokyo Japan. TASCAM established the Home Recording phenomenon by creating the "Project Studio" and is credited as the inventor of the Portastudio, the first casset ...

, 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, renders a ''DSD Disc''. Such discs can be played back in native DSD only on certain Sony VAIO laptops and

PlayStation 3 The PlayStation 3 (PS3) is a home video game console developed and marketed by Sony Computer Entertainment (SCE). It is the successor to the PlayStation 2, and both are part of the PlayStation brand of consoles. The PS3 was first released on ...

systems. Sony produced two SACD players, the SCD-XA5400ES and the SCD-XE800, that fully support the DSD-disc format. In June 2012, Pioneer launched a series of SACD players compatible with DSD-disc. The PD-30 and PD-50. In January 2013,

TEAC () is a Japanese electronics manufacturer. TEAC was created by the merger of the Tokyo Television Acoustic Company, founded in 1953, and the Tokyo Electro-Acoustic Company, founded in 1956. Overview TEAC has four divisions: *TASCAM - con ...

announced a DSD-disc compatible player, the PD-501HR.

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. 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. 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. In 2002, Philips published a paper arguing the contrary. Lipshitz and Vanderkooy's paper was further criticized by Angus. Lipshitz and Vanderkooy responded to the criticisms. Stuart also defined sigma-delta modulation a "totally unsuitable choice" for high-resolution digital audio. Conventional implementation of DSD has an intrinsic high distortion. 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. 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 to 6-bit 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 double-blind tests "hardly any of the subjects could make a reproducible distinction between the two encoding systems." In contrast, a 2014 study conducted at the

Tokyo University of the Arts or is a school of art and music in Japan. Located in Ueno Park, it also has facilities in Toride, Ibaraki, Yokohama, Kanagawa, Kitasenju and Adachi, Tokyo. The university has trained artists in the fields of painting, sculpture, crafts, inter ...

found that listeners could distinguish PCM (192 kHz/24 bits) from either DSD (2.8 MHz) or DSD (5.6 MHz) (but not between the two DSD samplings), preferring the sound of DSD over PCM: "For example, Drums stimulus of DSD (5.6 MHz) has p = 0.001 when compared against PCM (192 kHz/24 bit) in overall preference. This suggests that DSD version was statistically significantly preferred over the PCM version." These findings are questionable however, because "the two formats were subject to different processing, most notably, different filtering of the low-frequency content." 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 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

''DSD Interchange File Format'' (DSDIFF) is a native DSD file format developed by

between 2000 and 2004 for storage of DSD recordings. 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 A ''de facto'' standard is a custom or convention that is commonly used even though its use is not required. is a Latin phrase (literally " of fact"), here meaning "in practice but not necessarily ordained by law" or "in practice or actuality, ...

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 .dff file suffix. No official

media type In information and communications technology, a media type, content type or MIME type is a two-part identifier for file formats and content formats. Their purpose is comparable to filename extensions and uniform type identifiers, in that they ide ...

has been registered for the DSDIFF file format. Freedesktop.org uses the unofficial media types audio/x-dff.

Wideband Single-bit Data

''Wideband Single-bit Data'' (WSD) is a native DSD file format developed by 1-bit Audio Consortium in 2002. The consortium was established by

Waseda University Waseda University (Japanese: ), abbreviated as or , is a private university, private research university in Shinjuku, Tokyo. Founded in 1882 as the Tōkyō Professional School by Ōkuma Shigenobu, the fifth Prime Minister of Japan, prime ministe ...

, Sharp and Pioneer a year earlier. In 2012 the consortium published an updated 1.1 version of the specification. 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.

portable recorders MR-1, MR-2, MR-1000 and MR-2000s support WSD alongside other DSD based formats.

DSD Stream File

''DSD Stream File'' (DSF) is a native DSD file format developed by

around 2005. 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.dsf file suffix. No official media type has been registered for the DSF file format. Freedesktop.org uses the unofficial media types audio/x-dsf.

DSD compatible file formats

DSD-compatible file formats support storing DSD-encoded audio in addition to audio encoded as

WavPack WavPack is a free and open-source lossless audio compression format and application implementing the format. It is unique in the way that it supports hybrid audio compression alongside normal compression which is similar to how FLAC works. ...

is a generic audio storage format supporting various different forms of audio. Compressed DSD audio is also supported by the format. The DSD support was initially introduced with the release of WavPack software suite version 5 in December 2016. Files containing WavPack data would typically use the.wv file suffix. No official media type has been registered for the WavPack file format. Freedesktop.org uses the unofficial media types audio/x-wavpack. 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. 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. 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.

Notes

References

External links

* —DSD vs PCM comparison * , by Sony
How to make a DSD Disc using a Korg DSD Recorder
including DSD plug-in for

Windows Media Player Windows Media Player (WMP, officially referred to as Windows Media Player Legacy to retronym, distinguish it from Windows Media Player (2022), the new Windows Media Player introduced with Windows 11) is the first media player (application soft ...

* , DSD recording playback over

USB Universal Serial Bus (USB) is an industry standard, developed by USB Implementers Forum (USB-IF), for digital data transmission and power delivery between many types of electronics. It specifies the architecture, in particular the physical ...

software and hardware development kit
DSD downloads
{{Sony Audiovisual introductions in 1999 Audio codecs Audio storage Digital audio storage