Delta Sigma: An Inconvenient Truth

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by k4rstar, Jun 21, 2020.

  1. YMO

    YMO Chief Fun Officer

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    Don't forget the music, that's all.
     
  2. RobS

    RobS RobS? More like RobDiarrhea.

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    Music? What's that? I listen to gear.
     
  3. nishan99

    nishan99 Friend

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    Violins are very simple instruments, just give them the resolution they deserve and they will SING!. Look after that thing : ).

    ^ This
    My experience is always partially different from what I am expecting. No matter how much I research the thing, it's always different enough that I ask myself why even bother researching or reading all these discussions?. I know why... it's fun! : D , and also serves as a guide, not anything more than that.
     
  4. Mithrandir41

    Mithrandir41 Friend

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    No balls. Give it a try.
     
  5. RobS

    RobS RobS? More like RobDiarrhea.

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  6. Melvillian

    Melvillian Friend

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    I always feel like I’m hearing the weakest link in the chain regardless of whether it’s a transducer, amp, or source. I’ve gained a lot recently from moving away from USB and investing in a good SPDIF source. The hardness I always associated with digital audio is basically gone now and that’s something I wouldn’t have experienced if I’d only focused on parts of the system I felt were more important. As they say, the devil is in the details.
     
  7. RobS

    RobS RobS? More like RobDiarrhea.

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    I heard a lot of that hardness with Schiit's Gen 5 USB. But not all USB is bad. Unison, Convert-2s XMOS, Holo May, etc. But yeah sometimes the weakest link could just mean moving to a different digital audio interconnect. My problem in the beginning of last year was I had bought these cheap floorstanders which weren't very resolving and I spent too much time/money on getting a resolving source when that didn't matter. I read too much into DAC reviews that gave me the wrong impression they were the most important thing that mattered. I should have bought better speakers first, then the amp and then DAC/source. The whole chain still matters but what good is an expensive DAC if your speakers don't get the most out of it? My approach was ass backwards.
     
  8. purr1n

    purr1n Desire for betterer is endless.

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    I figured I would provide a visual analog of how DSD works.

    Here is a the original 8-bit photo
    AlexisTexas 8-bit.jpg

    The next step, we convert this photo to 1-bit, but at x64 times the resolution. This is essentially what DSD does. We trade bitdepth for sampling rate. The file is too big for me to upload, but I will provide snippets below of the 1-bit super-high resolution file.

    1-bit at x64 "sampling rate" at 12.5% zoom
    upload_2020-7-9_10-45-56.png

    1-bit at x64 "sampling rate" at 25% zoom
    upload_2020-7-9_10-46-26.png

    1-bit at x64 "sampling rate" at 50% zoom
    upload_2020-7-9_10-47-4.png

    1-bit at x64 "sampling rate" at 100% zoom
    upload_2020-7-9_10-47-37.png

    One thing to keep in mind is that if the original were an analog sample instead of an 8-bit, we would not be seeing the blocks. As an aside, noise-shaping would have to do with how the individual dots within each block or sub-block are arranged. Many possibilities here.

    Here is the 1/64 downscale of the above 1 and 0 bitstream Tron-world into the normal world.
    upload_2020-7-9_10-50-9.png

    There is actually a solid technical argument that DSD is "better" than PCM because the bit-depth at audio frequencies is effectively 30-bits or something like that. The implementations do sound different.
     
    Last edited: Jul 9, 2020
  9. Biodegraded

    Biodegraded Friend

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    What's most striking is that the conversion process preserves the nice broad stereo image :D
     
  10. Collusion

    Collusion Friend

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    Also the stage doesn't seem to be flat...
     
  11. robot zombie

    robot zombie Friend

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    But it is more than twice the size of your head, which is pretty unheard of. Normally this would make it too diffuse, but in this case its just a smooth, wholesome presentation. Just a lot to sink into.
     
  12. HotRatSalad

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    As a multibit guy for 2 years I really love my DS dac I have now. Of course I am only on the first couple ladder rungs in dac ladder. Also I would tongue punch that everywhere in black and white.
     
  13. yotacowboy

    yotacowboy McRibs Kind of Guy

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    TIL, "tongue punch in the fart box". Thanks, SBAF. Cheers.
     
  14. Raimei Templar

    Raimei Templar Friend

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    Slightly off topic but on the subject of DSD I have found that how good it sounds depends immensely on the dacs ability to process dsd. Many of the dacs out there dont actually play native dsd they use DOP, basically convert them to PCM first which wholly eliminates the reason to use DSD at all. Every Sabre based dac I have tried has done this, I am not sure if the Sabre chips are just not able to process DSD natively or if just the ones I tried failed to implement it correctly.

    Whenever I tried DSD with Sabre, I always thought it sounded worse than PCM.

    Burr Brown chips however are amazing with DSD, its one of their biggest advantages. I really wasnt all that impressed with DSD untill I tried it with the Zen DAC/Teac UD-501 where it was as good as PCM or perhaps better. Certainly wasnt worse. I dont recommend anyone going big on DSD unless they have a nice BB dac personally.

    I dont know how well AKM handles DSD maybe someone else can say, every AKM dac I have had didnt implement DSD.
     
  15. rlow

    rlow A happy woofer

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    DoP is just a packaging technique for DSD to be able to transmit using PCM “packets” for compatibility reasons, but it doesn’t actually “convert” the signal to real PCM data. When the packets reach the other end, they are simply “reassembled” and passed along as DSD which is exactly the same as the original. And apparently the processing power required to do this is mininal (compared to something like upsampling or digital filtering) so should really not be much of an issue. So I’m not sure that DoP is the real issue here - more likely just the difference in processing of the DSD by the Sabre DAC itself vs BB, similar to the variability in the sound quality of PCM from various DACs/chips.
     
  16. k4rstar

    k4rstar Britney fan club president

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    lol thank you @purr1n for the Alexis DACass visualization, I remember seeing it on Chang to demonstrate something similar. by using a black and white photo however we cannot see the manipulation of color and hue, only saturation, which is clearly less with the reconstituted image.

    further, music and our perception of music is a relationship of signal over time. the upsampling of a photo is not concerned with the time domain, we just want to reconstitute the signal at a higher resolution with minimal loss of detail. my argument is that the signal processing with delta-sigma conversion, although technically sound, causes irrevocable damage to the time domain which can be perceived by the ear as a loss of music.

    I understand not everyone experiences this phenomenon. your exposure to it does depend which genres and recording eras your musical pool consists of and there may be some acute sensitivity in individuals as well that has yet to be studied, not unlike Amusia (tone deafness)
     
  17. batriq

    batriq Probably has made you smarter

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  18. crenca

    crenca Friend

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    Not strictly true - there is but one waveform to rule them all. The waveform that strikes your eardrum, and is reproduced all along the chain, is a frequency/time relationship. We talk about two aspects when we say "frequency domain" and "time domain" but you can not strictly separate them.

    Why do you believe this? Have you ever seen a test signal that reveals phase fuckery inherent in DS architecture beyond the usual and variable digital/analog filters? Have you ever seen a theoretical argument by someone deep in the engineering along these lines?
     
  19. k4rstar

    k4rstar Britney fan club president

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    I'm not sure how/why you took what I said about the upsampling of a photo and applied it to me saying digitally sampled music is not concerned with the time domain, unless you are trying to say they are the same thing, which is a dangerous assumption to make

    yes the product of all conversion is one waveform with a strict frequency/time relationship. the waveform represents sound. music is not just sound, it is highly organized and complex sound and cannot be represented by a waveform. if you believe it can, this is a materialist and reductionist worldview that there is no arguing with.

    a test signal is not going to demonstrate the loss of music. I believe it because I would like to consider myself a rational thinker if not a scientific one and empirical testing with different recordings and equipment was enough to come to this conclusion for myself.
     
  20. crenca

    crenca Friend

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    Sound is but one and only one pressure wave in a medium - for our purposes the air that surrounds us and presses upon our eardrums. All the complexity of sound that you perceive from any source is contained in that one waveform. There is but one waveform to rule them all:

     

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