At first glance, difference between DSD and FLAC audio formats is outstanding. Except some limitations and features of each format, the comparison is very same to DSD / DSF / DFF / SACD vs FLAC / WAV / PCM. Many endless discussions, that format is the best, are there. But this question have no single answer. Read explanation and FAQ by audio software developer Yuri Korzunov why it so, about comparison FLAC versus DSD sound quality and watch video to study details below.
To understand, which is better DSD or FLAC, we should understand what they are.
FLAC (Free Lossless Audio Codec) is audio file-container format and compression method of recording or stream.
WAV also is file-container, that can contains compressed and uncommressed PCM and DSD in DoP.
FLAC, WAV, AIFF are lossless PCM implementations.
DSD (Direct Stream Digital) is audio recording or stream format by Sony, Philips. DSD sample rate is significantly higher than FLAC and other PCM (WAV, AIFF, etc.). And bit depth is reduced from FLAC's 16/24/32 bit to minimal 1 bit for Direct Stream Digital format. 1 bit is too low even for 2.8 MHz and higher frequencies. How 1-bit is allowable in Hi-Res audio read below.
DSD may be stored as DoP (DSD over PCM) into lossless PCM container (FLAC, WAV, AIFF, etc.).
DSD have implementations: DSF, DFF, SACD optical disk, SACD ISO file (image of SACD optical disk), DoP.
To be technically correct we compare implementations of both formats.
DSD vs FLAC comparison
Most popular DSD and FLAC comparison is listeing of single album by same label in two different formats.
However, DSD and FLAC (PCM) sound quality comparison is complex matter. Because there are many variables:
And all these variables are defined by implementation. Thus, it is impossibly to say exactly: what is sound better DSD or FLAC. Because it is need to study each case.
When we try to compare FLAC / WAV / AIFF ... other PCM and DSD album variants at home, it is easy to get sound difference due, as example, 0.5-2 dB variance between DSD and PCM circuits or software processing.
The variance may be considered as almost unlistenable as level difference. But we can get some impression of sound or audio quality difference.
So, before tests, it is necessary to compensate level difference between DSD and PCM outputs to 0.1 ... 0.2 dB approximatelly. It allow to avoid getting of imaginary sound difference due various levels.
Otherwise, we risk to get "better quality" for louder DAC or DAC mode.
As example, one person have louder PCM output and like FLAC. But other person have louder DSD output and prefer DSD. And they can have endless discussion "what is better".
And it is only 1 control goal, when the listening test is performed. And there are many details, that are invisible at first sight.
Read about hi-fi blind tests >
To DSD and FLAC format comparison:
Main difference between FLAC and DSD is kind of musical signal modulation. Or kind of analog signal coding to digital form. Further we consider difference of the modulations.
Bit depth of DSD is reduced to 1 bit. But it cause huge quantization error noise and low signal-noise ratio. To improve the ratio, noise energy is pushed out the audible frequency range.
Bit depth reducing demands frequency range reserve for noise energy pushing. The range reserve may be added by higher sample rate.
DSD sample rates: DSD 64, DSD 128, ...
FLAC sample rates: up to 384 kHz.
The range reserve cause useful DSD audio band reduction, comparing [sample rate]/2 band of PCM.
DSD is intended for audible range transmission. DSD64, as rule, have almost flat noise in band below 20 ... 24 kHz. Above this band noise level grow with frequency. Aforementioned figures depend on implementation.
DST (Direct Stream Transfer) is size compression method for DSD audio stuff. It is implemented in DFF and SACD ISO files. DSF have no size compression ability.
FLAC format is intended for size compression primarily. But there is opinion (without objective evidence, known for author), that computing for FLAC uncompressing cause additional interference, that degrade sound. To avoid unpacking, uncompressed FLAC is used. The FLAC is used because it contains metadata standard way.
FLAC file-container also can contains MQA-compressed audio stuff. Such FLAC may be played back without MQA-decoding.
As rule, PCM DAC, intended for FLAC playback, is based on sigma-delta modulator and demodulator. The demodulator is low frequency filter.
DSD DAC can contains the filter only.
Text metadata (album and track names, performer, etc.) contains in SACD ISO, DSF, FLAC files standard way. DFF have no standard metadata support.
SACD ISO and DFF don't support artwork metadata standard way. FLAC and DSF both can contains multiple artworks (album cover, band photo, etc.)
Despite DSD give some audio-equipment-design advantages to achieve better sound quality, only audio device implementation define actual audio quality of a device. How to look for the best quality of your audio system read here...
AIFF is more flexible format (almost non-limited audio resolution, but some limitations with file length more 4 GBytes). FLAC have great compatibility with music devices and software. For sound quality AIFF or FLAC is no matter. Read more...
DSD512 is sample rate 22.6 MHz=44100 Hz * 512. Read more...
DSD music is music proviced in DSD format. Some of DSD music samples are recorded in DSD and distributed without editing. Read more...
DSF is one of formats of DSD files by SONY. Read more...
It depend on recording and equipment. Read more...
DSD audio is method of coding of an analog signal in a digital form. Read more...
WAV (Waveform Audio File Format) is format of audio files. Read more...
Yuri Korzunov (Audiophile Inventory's founder), 2018-2019
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