What's DSD audio in Hi-Fi?
How DSD works? Explained
Is DSD better than FLAC, WAV, PCM?
Where can you listen to DSD audio?
Frequently Asked Questions
What's DSD audio in Hi-Fi?
How DSD works? Explained
Is DSD better than FLAC, WAV, PCM?
Where can you listen to DSD audio?
Frequently Asked Questions
DSD audio file conversion
Probably, you already read articles, that explain DSD audio (Direct Stream Digital). But it may not easy still understand why 1-bit-only DSD may successfully compete with ordinary multibit PCM.
Read simple explanation what is DSD and how it works, what's sound quality, DSD vs PCM, myth debunking and other essential issues by audio software developer Yuri Korzunov.
DSD (Direct Stream Digital) is an audiophile high-resolution audio format. It is a method of coding analog signal to digital form via sigma-delta modulation. Initially, it was designed an alternative to PCM (Pulse Code Modulaion), that used in CD-audio, WAV, FLAC, mp3 and other formats.
Audio signal is an acoustic oscillations (sound) converted to the same electrical ones with microphone.
Digital form of an audio signal converted to a number sequence.
The sequence allows create the electrical oscillations back.
An audio signal (the electrical oscillations) may be presented as DSD or PCM.
It’s like we can assemble the same mosaic from small squares or circles.
Below we’ll return to the methaphore.
Both DSD and PCM are a sequence of measured values (samples) of an audio signal's oscillation.
PCM shows position of the oscillation (sound/air pressure level).
The pressure level after microphone was converted to an electrical voltage. Thus, to measure the pressure, we measure voltage level at the microphone input periodically.
Each such measurement value is called "sample".
In sigma-delta modulation (a.k.a. DSD) each number (1-bit) shows a positive [1] or negative [0] the pressure's level altering relative the previous pressure level.
And, as rule, DSD is explained as a saw (level grow or fall) between samples. But, it did not give an easy understanding of the basical DSD principle. Below we'll consider the easier explanation.
Read:
Audio CD optical disk (PCM modulation / PCM format) was one of the first digital formats. It was a source with low distortion and noise level comparing analog ones. I think, now many people forgot what is "real analog noise".
From CD (PCM) to SACD (DSD)
After CD, demands to sound quality improvements could be implemented by increasing sample rate or bit depth.
Audio quality (sound quality) is a level of noise and distortions, that cause format/software/equipment. The level may be normalized by psychoacoustic criteria.
However, Sony and Phillips decided to use another kind of modulation - 1-bit sigma-delta modulation. At first glance, using of 1-bit is impossible, because such bit depth (resolution) causes huge noise level. But, if high sample rates are used, noise energy may be pushed out of audible frequency range (to ultrasound). That action is called "noise shaping".
Practically, 1-bit conception may be easier, than multi-bit, in a DAC implementation (read below).
When DSD music is converted to analog, ultrasound noise is filtered.
Medium, which contains 1-bit DSD audio stream was called SACD (Super Audio CD).
Look at DSD file infographic >
Abbreviation of: | Direct Stream Digital |
---|---|
Audio data coding method: | sigma-delta modulation (details and video) |
Bit depth: | 1 bit or more (details about sound quality) |
Sample rate: | DSD64 (2.8 MHz), DSD128 (5.6 MHz, double), DSD256 (11.2 MHz, quad), etc. (details) |
Channel number: | Stereo or multichannel |
Medium: | SACD optical disk, including hybrid SACD (with CD layer), computer files [SACD ISO (ripped albums from SACD) and DSF, DFF, CUE+DSF/DFF] (details) |
Specification: | "Scarlet book" (1999) |
Applications: | Music production, home hi-fi/hi-end audio |
Direct Stream Digital is one of high-resolution audio formats to improve CD-audio dynamic range in the audible band.
Read below about sound quality issues (noise, bit depth, band, sample rate, DSD versus PCM).
As rule, DSD has been explained in the time domain: positive samples increase level, but negative decrease and analog filter smooth "saw" form of signal.
Into DSD analog-to-digital converter (ADC), measuring "saw" signal is compared with input analog signal.
At the ADC output "1" is present. And measuring-signal level grows until it exceed current level of the input analog signal.
It causes the output signal switching to "0". And measuring signal begin to reduce level.
When the measuring signal level is a lesser input signal of the ADC, its output is switched to "1". And measuring signal grows until the exceeding of the input signal.
Read how to sigma-delta modulator works...
Above we discussed DSD vs PCM like mosaic from squares and circles.
These figures may be significantly smaller of the assembled image. If our eye can't rersolve the figures, there is no difference squares or circles we are used.
So, qualitative DSD and PCM system can bring us the same final result.
Such explanation causes difficulties in understanding what is actual difference between PCM and DSD and how to process DSD. Probably, it creates myth about "native" DSD processing. About the processing read below in "DSD editing software" part.
Instead the explanation, in the author's opinion, the easiest way to understand how to DSD works and process it is its spectrum consideration.
To estimate DSD and PCM sound quality, the quantization-noise level is main criteria.
There is an explanation, that DSD has super high sample rate and, thus, super low bit depth 1-bit does not matter for noise.
But DSD 64 sampling rate (2,8 MHz = 44.1 kHz * 64), it is not enough to be better CD audio (see details).
To decrease noise level, noise shaping is used.
1-bit quantization-error (noise) energy has a significant level.
However, there is, so-called noise shaping of the spectrum is used. And quantization-error energy is re-distributed.
Noise shaping (NS) of 1-bit signal (spectrum)
Noise shaping in the simple words
Lit's imagine noise energy as water in a pool.
If we blow strongly to the water surface at one pool side, at this side water level is decrteased (noise is decreased in audible range).
It is the same adding more bits of audio resolution.
The water will be displaced to other pool side (inaudible ultrasound range). And level there grow.
The quantization-noise spectrum (at the left of the picture) has a level comparable with a musical signal. Sigma-delta modulator pushes significant part of the energy from low to high-frequency range, out of audible band (0 ... 20 kHz).
Noise shaping is implemented in sigma-delta modulator (a.k.a. DSD modulator).
When the 1-bit record is played back, a low-frequency filter into a sigma-delta demodulator (a.k.a. DSD demodulator, DSD decoder) cut the noise.
DSD decoder (demodulator)
Therefore, at spectrum error level into the audible range is comparable with multibit pulse code modulation's (PCM) one.
Also, sigma-delta modulation may have multi-bit resolution. Read details below and watch the video on this page.
The format use standard range of sample rates based on 44100 Hz:
Also, 48000 kHz base is possible. There are no technical limitations for the sample rate value. But hardware/software compatibility issues are very probable.
For Nyquist theorem no difference between DSD and PCM: spectrum above [sample rate]/2 is the same to the spectrum below [sample rate]/2 and flipped along frequency axis.
When sigma-delta modulator is designed, the engineers pay attention to two main parameters:
To solve these issues the engineers have:
These parameters should be considered comprehensively.
Bit depth reduces quantization error level as itself.
NS "push" significant part of the quantization error energy out of audible range.
We can suggest that more energy may be pushed out of audible range in sigma-delta modulator. But it requires steeper noise shaper.
Steeper NS can cause a higher probability of glitch (broken stability) of a sigma-delta modulator when input overload happens.
After the glitch, silence or some oscillations are generated at the output of sigma-delta modulator.
After broken stability, the modulator should be forcibly reset.
Higher sample rate reduces error spectrum level due distribution of its energy into a wider band. Also, it gives the ability to use sloper NS.
Energy is square of the figure, concluded between spectrum line and horizontal axis into band 0 ... [sample rate]/2.
At the left and right pictures, squares of the noise energy figures are same. But figure, that more expanded in the horizontal axis, give lesser noise level.
Higher sample rate allows reducing the noise level in audible frequency range. It allows reducing noise shaping steepness, that increase overload tolerance of the modulator.
We can see that lower noise and higher stability to overload can be achieved in different ways.
As an example, better quality is noise shaping implementation matter for the same bit depth and sample rate. But, on the other hand, we can increase the sample rate and/or bit depth to decrease error level for the same NS method.
Pro audio modulators have noise level in audible frequency range for sample rates (read details):
Noise level in the audible frequency band almost don't depend on demodulator. But the noise should be maximally suppressed out of the band. Ultrasound noise can cause audible intermodulations distortions.
Read more about DSD vs DSF vs DFF >
No. Both format quality is defined by implementation in a device and software.
Also played back record is matter.
DSD's low noise level is a result of noise shaping.
DSD bit depth define noise level abilities. After DSD editing sigma-delta remodulation is need.\
Read more about DSD editing...
The editing with decimation is implemented with low-frequency filter. The filter cause ringing audio.
However, no serious researches, that author know, studied the real impact of ringing to ears.
Also, the ringing depends on filter implementation.
So, currently, we don't know the exact answer to the question.
Bit depth define audible noise. More bit depth is lesser noise.
At the picture, we can see that bit depth decreasing achieved through using only part of the full signal frequency band. Other words, if we want to reduce bit depth, we must increase the sample rate to keep the audible noise level.
Read details of the format comparison in the table: DSD vs WAV vs PCM vs FLAC vs DXD
Fea |
DSD | FLAC | WAV | PCM | DXD |
---|---|---|---|---|---|
Coding |
sigma-delta modula |
pulse code modula |
pulse code modula |
pulse code modula |
pulse code modula |
Samp |
44100 x 64 x N | up to 384'000 Hz | up to 2'147'483'648 Hz | no limit | 352 / 705 kHz |
Bit depth |
1 bit, |
16 ... 24 bit, |
16 ... 64 bit inte |
multi |
24/32 bit |
Band for audio signal | Low part of the band | Full band | Full band | Full band | Low part of the band |
Medium | file, optical disk: SACD | file | file | file, digital tape, optical disk: CD, DVD |
Note: WAV and FLAC are PCM implementations.
Read which is better DSD or FLAC (Infographic) >
Read more about audio file formats >
Direct Stream Digital (sigma-delta modulation) is like to pulse code modulation, but quantization error spectrum is shaped for decreasing noise into the audible range.
We can apply NS for usual PCM. But the difference here is band reserve for pushed noise out of audible frequency range.
PCM have lesser band reserve (above audible range) than sigma-delta modulation format, but pulse code modulation has higher bit depth.
Noise shaping for pulse-code modulation is implementation matter too, like sigma-delta modulation.
Therefore, no format advantages as itself. But implementation makes a difference.
Sigma-delta-modulation decoder (demodulator) is 2-position (1 / -1) voltage generator and low frequency filter. It is simpler than pulse-code-modulation hardware demodulator. Because pulse-code demodulator contains multi-voltage matrix or 1-bit decoder(s). So we have more abilities to make cheaper 1-bit DAC better than multibit one.
Read details here >
Also, look to infographic DSD versus FLAC >
There is no univocal answer. There is several reasons:
These reasons trigger infinite discussions "what is better PCM or DSD".
Technically, DSD and PCM are incomparable. Even as single DSD/PCM compatible DAC is used for the test, the difference may be caused by different mixing/post-production of records, and the DAC uses the different circuits (see here).
General answer: "Each case is individual and depend on playback system implementation and listened to record".
There is no unambiguous answer to the question. It depends on record quality, your software and equipment.
There is no answer. Theoretically, DSD has better potential than FLAC and other PCM formats. Recording, certain equipment makes sound quality. Read details...
1 minute of DSD64 stereo is about 40 Mbytes.
See more...
Yes. Hybrid SACD also may contain CD layer compatible with usual CD player.
.dsf, .dff, .iso (sacd iso), flac/wav (DoP). Read details...
Sound is defined by record quality, your playback program and apparatus.
Upsampling can optimize audio file resolution to optimal (minimal playback distortions) for your equipment. Read details >
Read DSD store site list here >
Look at:
Also read: DSD player F.A.Q., DSD converter F.A.Q., Myths
You can listen to .dsf (DSD audio files) here:
Both kinds of DAC contains sigma-delta modulator. It converts the analog voltage to digital samples in a format like to DSD.
Before modulator analog filter ["DSD" sample rate]/2 is applied. Looks details here >
PCM ADC is more sophisticated and contains multibit modulator.
To reduce sample rate "multibit-DSD" signal should be filtered (low-frequency filter) and decimated (removing part of samples). The filter also eliminates shaped noise of "DSD signal".
Read more about PCM and DSD difference >
To easier providing of PCM DAC precision/linearity into this kind of DAC, a digital sigma-delta modulator is used. After it, sigma-delta de-modulator convert digital "DSD" to an analog signal.
In the general case, DSD DAC is simpler. It contains sigma-delta de-modulator only.
It is technically impossible to compare PCM and DSD DACs, because they use different processing / electrical circuits.
Read more what is DSD and PCM DACs and their comparison >
DSD editing is cutting, merging, gain altering, equalizing, etc. of file(s).
"Native editing" (without conversion to multibit and DSD re-modulation) is possible for cutting and merging DSD records only.
All other kinds of editing demand conversion to multi-bit values and re-modulation. In this case, loses of the editing in itself, comparable with PCM resampling.
Read details here >
SACD disc may be losslessly converted to SACD ISO [1], [2], [3].
SACD ISO image may be extracted to DSF and DFF files. Lossless extraction may be applied.
1-bit audio files (DSF, DFF, SACD ISO) and disks may be either uncompressed or compressed with DST method.
DoP is an open protocol that allows pack 1-bit audio as multibit for compatibility with software and hardware [4]. DoP cannot be played as usual pulse-code modulation.
Also, 1-bit audio may be streamed via a network.
Uncompressed DSD64 demands capacity 2.7 Mbit/sec = 44100 Hz * 64 / 1024 / 1024.
Also, index file CUE + DSF/DFF audio files may contain 1-bit album.
Look at "DSD files" infographic >
DSD may be played at a mobile phone, portable players, music servers, SACD-players and other devices.
Some device can support native DSD feed of DSD DACs. Other ones demand pre-conversion to PCM or make conversion "on fly".
Sound quality is a complex matter. Read details about the resolution of audio files and sound quality.
Read details how to open, play DSD on Mac, Windows, iOS, Android, Linux: player list >
Read how to download DSD music and how to get free DSD files here >
DSD audio players (hardware and software) can playback all or some of the 1-bit file formats.
1-bit files may be played back directly on DSD DAC/player or converted to PCM "on fly" to playback to PCM DAC/player. About SACD conversion read more here
1-bit playback may be performed via special ASIO-driver under Windows, including DoP (DSD over PCM) digital audio packing format (example).
SACD optical disks may be played back at hardware player. Author knows nothing about available SACD-drives for consumer computers to playback/record SACD optical disks.
A stereo player may downmix multichannel to stereo. As alternative multichannel files may be pre-converted to stereo. It allows saving space on the hard disk of an audio player. Downmix is lossy audio processing. Its quality defined by an implementation.
Read more about the players here > and here >
Read DSD player software list >
To play DSD audio, use DSD audio players...
Yes with additional software. Read details here
Yes. Read details here...
As the author know, not. Read details...
Yes. Look at the player list...
As the author know, Vox convert .dsf and .dff files to PCM on fly without native DSD playback.
As author know, Plex can playback DSF. Details
As the author know, yes. Details
Yes. Look at the player list
As the author knows, there is conversion to PCM files is necessary.
Yes, Mac can play DSD...
Also read: DSD converter F.A.Q., DSD F.A.Q., Myths
Read details how to convert DSD on Mac, Windows and other platforms: converter list >
How to create, edit DSD files read here >
How to rip DSD from SACD (to SACD ISO) read here
DSD converter is software that can perform (depend on implementation):
Read how to works the converters here >
Look at DSD converter comparison list >
Convert DSF/DFF/SACD ISO to *m4a (ALAC, Apple Lossless). Read also (conversion DSF/DFF/SACD ISO to ALAC(m4a) is same) DSF to FLAC, DFF to FLAC, ISO to FLAC.
Conversion with processing audio (including DSD to PCM) adds distortions. But final distortions is a matter of used playback distortions. Read details here
It may be lossless when audio converter doesn't process audio stuff (resampling and other) in conversion.
Yes. There is noise level, frequency/phase distortions and tolerance to overload are estimated. Read details here.
Also read: DSD player F.A.Q., DSD F.A.Q., Myths
Read main article about DSD editing >
DSD editing is sophisticated issue due modulation noise. Non-linear processing can cause audible intermodulation distortions by ultrasound noise.
Currently no information, that is known for the author, about "native" 1-bit processing (example: gain altering, resampling, etc.) without conversion 1-bit to multibit and back. Except, merging/dividing the audio file.
Read the article about DSD versus DSF versus DFF >
PCM here may be considered as "multibit DSD". Pulse code modulation is not obligatory to mean "24 bit / 352 kHz" or so on. Author recommends use 32- or 64-bit float point bit depth. This PCM contains high frequency modulation noise. But for conversion, this "multibit DSD" to 1-bit need re-modulation with NS.
Losses of editing with 1-bit/multibit conversion are comparable with resampling.
Recording studios may distribute 1-bit records without editing.
DXD is PCM (as rule "24 bit / 352 kHz" or so on) with high sample rate and bit depth and legacy DSD noise. However, the noise can cause audible intermodulation distortions. Before non-linear processing, the high frequency noise cutting is recommended.
DXD is PCM with noise hump in high frequencies. DSD DAC is simpler than PCM one in theory. From DAC point of view, DSD is ideal format. But, actual result is refer to digital-to-analog converter model. Read details here...
There are compatibility and other issues of tranfer 1-bit and multibit audio data from computer to PCM or DSD DAC.
All audio interfaces (USB, in instance) are designed for multibit data. And 1-bit data packing into ordinary multibit value was suggested.
DoP (DSD over PCM) is a format providing compatibility with some DSD hardware (USB DAC, for example). The format allows packing 1-bit DSD data in usual multi-bit words (like PCM).
These multi-bit words are transferred as usual PCM. Upper bits of the multi-bit word contain special "DSD over PCM" marker code.
DoP receiver should recognize the marker code and interpret lower part of the multi-bit word as raw DSD bits.
DoP format may be stored into usual lossless PCM file: WAV, FLAC, AIFF.
DoP coding may be chosen in audio player settings.
Audio samples may be downloaded here:
Check more DSD downloading resources >
Read the detailed article about DSD >
DSD is 1-bit audio data (sigma-delta modulation) format for hi-fi audio.
For the same sample rate and bit depth, the format may have different quality, that depends on implementation.
DSD digital-to-analog converter is simpler than the PCM one. It allows getting the better quality simpler way.
DSD may be edited via 1-bit to multibit and back conversion. The edition is lossy, except merging/dividing.
DSD has multiple meanings. In audio, DSD means Direct Stream Digital format. Read details...
SACD is optical disk that contains digital audio data in DSD format. Read more...
DoP format is protocol for audio unit interaction. The protocol contains DSD audio data. Read details...
DSD is well known audiophile format. It allows achieving high sound quality and often used for classic and jazz music recording.
Read more...
Both DSD and PCM have advantages and disadvantages. Its discussing is theoretical rather. Read details here...
No. DSD is alternative audio format to PCM one. Read more information here...
DSD and PCM lossless files are the highest-quality audio files. Read details here...
DSD and PCM bit depth may be compared by quantization noise level in the audible band. However, equipment and software play big role there. See approximate comparison DSD and PCM bit depth...
FLAC format supports high-resolution audio. It give technical abilities to better sound quality.
Read details here...
DSD streaming service you can find here...
DSD is family of high-resolution audio formats. FLAC is one of PCM audio formats.
Read details...
DSD is lossless audiophile format. mp3 is lossy PCM format. Also, mp3 is hi-fi format at high bitrates.
Technically, DSD is better than mp3.
Read more...
You can play DSD files with special hardware and/or software.
Read details...
DSD music can be played on a computer via DSD player software...
To play DSD you can use DSD audio player or iOS/Android mobile phone.
Also, you can play DSD on computer with ordinary PCM audio card.
It's possible either:
If you have external DAC (DSD or PCM), you can connect it to the computer or player device.
Read details...
DAC is required thing to playback music. However, you can play DSD at traditional PCM DAC.
You can:
DSD over PCM is packing method of 1-bit audio to ordinary PCM format.
Read details...
You can play DSD music under Windows. Read more...
As the author know, VLC player software can't play DSD files. Read the discussion...
Spotify doesn't support DSD audio. Read about DSD streaming service...
Qobuz does not providing DSD streaming. Check out DSD streaming service...
Here you can look for DSD music files:
Author: Yuri Korzunov,
Audiophile Inventory's developer
July 2, 2022 updated | since December 25, 2017
Copyright © Yuri Korzunov
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