Is there a better digital audio format?

June 22, 2021
 by Paul McGowan

9 comments on “Is there a better digital audio format?”

  1. I don’t think we can say that anyone chose PCM over DSD. The original CD introduced in 1982 holds about 700 Mbytes of audio data giving 74 minutes playing time. The 64 times PDM encoding we use for DSD needs 64/16 = 4 times as much storage. I don’t think there would have been a market in 1982 for a DSD format with 18.5 minutes playing time, when most vinyl releases provided 44 minutes.

    Secondly, PDM is generated inherently by delta-sigma converters. Correct me if I’m wrong, but I think that all ADCs and DACs were R/2R in 1982.

    1. PCM was chosen as a digital recording format in the early 1970s. The first machines were produced by Denon and there was already a significant number of PCM digital recordings issued on vinyl long before CD. These are mostly classical and classical was used to market CD when announced in 1979. The issue then became the size of the disc. Studios who had invested in PCM recorders weren’t going to switch to something else, and there wasn’t something else because PCM was universally agreed and accepted at the time.

  2. In his answer, Paul acknowledges that it is almost impossible to carry out digital operations directly on PDM. The mixing, EQ, compression, reverb and similar operations needed for mixing “in the box” can only be used by transcoding to/from PCM. Common sense suggests that the purity of DSD is compromised once and for all on the first transcoding operation. It’s hard to see that DSD-PCM-DSD could be preferable to native PCM. I wonder if the reason that DSD is still preferred is that the PCM transcoding is to very high resolution PCM. In that case, can we assume that hi res PCM is as good as DSD?

    1. Good afternoon Mark!
      To answer your question, the 2 parted answer is, both yes and no.
      Sure you could make a higher rez PCM file, but it will never sound nearly as good as native DSD.
      There are a lot of hoops that has to be jumped through to get it right the first time.
      But it’s not a real easy task to perform either.

    2. Mark, I’m assuming your question was rhetorial? If so, I think your point was well made. If you consider Sony’s original intention (AFAIK), DSD was developed as an archival solution to preserve the degrading content on the magnetic media used for their library. So perhaps DSD was only ever considered as a medium for their ‘master recordings’ and not intended to be ‘edited’? At any rate, they must have felt confident that recording ‘masters’ in DSD was at least as accurate as recording on magnetic media. I think that the ‘quality’ of any downstream processing is moot so long as the ‘master’ retains its integrity.

      Your point about DSD’s storage requirements is also well made. At the time of its development, data storage media was relatively large and expensive. Add to that Sony’s mistake (IMO) of locking away the DSD layer in a proprietary SACD standard, it’s no wonder DSD has not gained a greater acceptance. Today the DSD format is publicly available but unfortunately SACD is still not.

      1. Mike, the question wasn’t entirely rhetorical. I haven’t heard the difference between DSD and PCM, but I think we have to trust Paul when he says that DSD is superior. If this is the case, it is curious that transcoding between DSD and PCM during mixing and mastering should introduce only the very smallest degradation. Repeated transcoding operations can’t be a good idea, so an unbiased or uninformed observer would likely conclude that a better approach would be to convert to PCM once, and to keep the PCM throughout the mixing and mastering, and then convert back to DSD for distribution. I was speculating that the use of very high resolution PCM might be the reason that the PCM transcoding introduces an almost unnoticeable degradation.

        My understanding of the history of DSD is that Sony engineers decided to use the PDM output of their delta-sigma ADCs when archiving analog masters. This makes sense, because it is the earliest point in the signal chain where there is a digital signal. They reasoned that they could transcode to PCM or any other format in the future. As you say, in this era there was no need or intention to edit the DSD recordings. The delta-sigma ADCs of course produced a PCM output as standard. Subsequently, Sony marketing and product managers found out about the PDM recordings and decided to promote DSD as a high resolution format for consumers.

  3. Paul, DSD and direct to disc have the common characteristic that they can not be edited. So to do a pure DSD recording it would have to be played once from start to finish which is done every day in live performance and is even often preferred to a manipulated one even with minor glitches for its spontaneity. You implied pure DSD is better than DSD/PCM/DSD. Have you ever considered doing a pure(direct to disc?) DSD recording?

  4. DSD is either recording analog or preserving analog. Musical instruments are analog. The human voice is analog. The microphone is analog. Unless you throw out vibrating drums, cymbals, guitars, bass, horns, and the human voice and replace it all with soulless synthesized fully electronic music than you are hearing analog recorded by or preserved by DSD. Many still believe the best way to play back analog is on analog playback systems. Digital is the best way to preserve analog since nobody cares about improving on analog recording, storing, and playback systems, so enjoy your purely analog experience while it lasts. The digital heads want to kill off the pure analog experience by not improving on preserving it on analog format.

    1. Good morning Joe!
      Sorry for being late in posting a response to you.
      Please forgive me!
      I’ve read quite a few articles that suggests, that all that is about to change.
      If you stop to think about it, we have the resurging of vinyl.
      And there is also talk going around, about both reel to reel and cassette tapes making a resurging too as well.
      However, it all is aimed at the high end market.
      But give it more time, the prices will fall low enough, that the rest of us will be able to enjoy it.
      So, no.
      I don’t think that analog is going away, anytime soon.

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