100% Natural Sounding Digital Reproduction: Is It Possible???

Discussion in 'Audio Hardware' started by Khorn, Dec 15, 2004.

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  1. Khorn

    Khorn Dynagrunt Obversarian Thread Starter

    What digital resolution would be required to exactly reproduce an analogue musical waveform with all its components in the Digital domain. Will it ever be possible? That is the probably the only way there will ever be close to really natural sounding digital reproduction. IMHO once electronics are introduced into the chain 100% natural sound is "out the window" anyway but, how close do you think we could get and what type of digital resolution would be required?

    Maybe (but I doubt it) some of these new high density formats (like Blu-Ray) might have enough space to accomplish this.

    Any thoughts?
     
  2. fjhuerta

    fjhuerta New Member

    Location:
    México City
    SACD is the most consistent format right now in this regard, IMHO, although I should add that the Classic Records HDAD's blow me away all the time, too.

    Maybe the formats are capable of this kind of resolution, and it's just a matter of time until engineers manage to squeeze the last bit (no pun intended) out of them.
     
  3. Metralla

    Metralla Joined Jan 13, 2002

    Location:
    San Jose, CA
    The studios do it today - and have been doing it for a while. We don't get to hear those wide bandwidth digital versions, as something has to be compromised to get the digital information to our homes.

    We've seen improvements - SACD, for example - but according to insiders the DSD tapes sound better than the optical disc.

    Perhaps in order to get the full resolution we need a different delivery system, and Blue-Ray could provide that. I'm pretty happy with SACD; but I'd like to know what I'm missing.
     
  4. Vivaldinization

    Vivaldinization Active Member

    I don't understand your question.

    For one, you use the word "natural," which I don't think actually means anything quantifiable. At what point can we agree on what constitutes a "natural" digital sound?

    Secondly--and this bears emphasis:
    A CD quality waveform--16 bit, 44.1kHz--completely reproduces the frequency response of an input wave of about 22kHz. This is a rule according to Nyquist.

    Again: COMPLETELY reproduces. There isn't anything lost, and the digital stream is more than capable of reproducing everything.

    Misunderstandings tend to come into play when people misinterpret what the various digital formats really mean. People look at 44.1kHz and 16bit audio, and they imagine that what they're hearing is a sequence of discontinuous samples fired past "too quickly" to hear, turning into what sounds like continuous audio. This isn't how digital works. The DA converter turns those samples into a continuous waveform.

    Thus, back to your query. What is "natural sound?" OK, so let's give an awful lot of headroom. Most people can't hear above various frequencies in the 20kHz range, so let's get a bit crazy and double that. 44.1 kHz. Wow, is that a huge frequency response! It reproduces a lot of the supersonic harmonics which people crave. Let's increase the bit-depth of our signal to 24bits, to give us an easier time processing in the digital domain (no dither!) and to give us even more dynamic range that we won't use in 99% of popular music.

    So our new, fantastic bit depth and sampling rate: 88.2kHz, 24bits.

    Is this "natural?" I don't know. It reproduces all frequencies up to about double that where most people's hearing stops cold, without entering into the supersonic-deadliness stage of DSD. It has an absurdly huge dynamic range. It can completely and accurately reproduce the entire frequency response of the Rolling Stones' "Satisfaction." (Then again, CD quality audio can do this too)
     
  5. Ken_McAlinden

    Ken_McAlinden MichiGort Staff

    Location:
    Livonia, MI
    If you want to nitpick, one could argue that there is no such thing as a 100% natural sounding recording in any analog or digital format. :)

    Regards,
     
  6. Luke M

    Luke M New Member

    Location:
    Pittsburgh
    Since plain old CDs are capable of high fidelity, I wonder what sort of miracles you expect? You can't get thrills by jumping off a pancake (unless you are easily thrilled).
     
  7. Khorn

    Khorn Dynagrunt Obversarian Thread Starter

    I guess that is what I'm getting at. Maybe I should have substituted the word "Live" for "natural".

    Now, using "live" as the benchmark how close can the digital electronic process come to reproducing it? One thing that stands in the way of "live-like" reproduction is the unavoidable "electronic signature" introduced in various forms at all stages.
     
  8. therockman

    therockman Senior Member In Memoriam


    I don't think that you should be making blanket statements like this because they may discriminate against entire groups of people. I am sure that all of the "pancake jumpers" out there might feel insulted by these very general remarks against pancake jumping.
     
  9. Vivaldinization

    Vivaldinization Active Member

    I understand what you mean...it's usually fairly easy to tell a "live" sound from a recorded sound. That said, I think that has to do with elements of production and expectation that go far beyond the science of audio reproduction.
     
  10. thxdave

    thxdave "One black, one white, one blonde"

    I don't we should be waffling on this pancake issue either. I'm tired of getting battered around in these specious argurments. You'll either find it exciting or not...just don't step in the syrup, please. <somebody PLEASE help me!>

    As to the benefit of whatever high-res formats either extant or coming, I think that we already have a benchmark to aim for. In this case, it would be the Master tape itself. That's our only frame of reference and the closer we can come to reproducing it, the better. Since very few of us here were sitting in the room when these great recordings were made, we will NEVER know exactly what those instruments sounded like in that room at that point in time. Also, so many of these great performances were put together like Tinker Toys over an extended period of time.....there really wasn't a "performance" captured....just a finished product. At least the Master tape is there as a reference but, with a few exceptions (Hi Steve) we know how often other folks miss the target of what the Master sounded like.

    Didn't Sony start a big campaign of archiving their catalogue on DSD? Since the original analogue tapes are prone to degradation over time, I guess this was a good bet as a way of stopping the aging process. However, only time (and maybe High Res Audio) will tell.
     
  11. Cheepnik

    Cheepnik Overfed long-haired leaping gnome

    thxdave's favorite album: Hotcakes by Carly Simon, followed closely by Breakfast in America.
     
  12. thxdave

    thxdave "One black, one white, one blonde"

    D'oh, 'ya got me!!
    <thinking....thinking>
    "Darn brain"
     
  13. thxdave

    thxdave "One black, one white, one blonde"

    Actually, I prefer groat clusters. "Heavy on the 30 weight, mom!"
     
  14. Khorn

    Khorn Dynagrunt Obversarian Thread Starter

    OK, sounds reasonable enough but wait...there's this next part:

    We have a master tape and then copy it for reproduction to a consumer hi resolution format. The operative word should be "copy" here. The only limitations in duplication should be the resolution of the format being copied to therefore it (the copy) should sound identical/nearly identical to that master tape unless somebody does something and why would/should they if the ultimate goal is an exact copy of the master? Problem is they do do things.....why??? Once you start doing things (in the copying process) you are stepping into the 'artistic domain' and true fidelity sort of goes out the widow. What's left is your interpretation. Is this good or bad and under what circumstances should it be justifiable???
     
  15. Cheepnik

    Cheepnik Overfed long-haired leaping gnome

    Let me guess, you were just upstairs helping Porcelain make the bed. :agree:
     
  16. Metralla

    Metralla Joined Jan 13, 2002

    Location:
    San Jose, CA
    Please.
     
  17. BIG ED

    BIG ED Forum Resident

    Thanks for putting smile on my face, guys!
    And thanks for the reminder that CD's were as close to the master tape, as the general public had ever gotten at the time.
     
  18. Metralla

    Metralla Joined Jan 13, 2002

    Location:
    San Jose, CA
    Huh? How did you figure that?
     
  19. Vivaldinization

    Vivaldinization Active Member

    Please what? Supersonic noise can be a problem with certain DSD implementations.
     
  20. Mal

    Mal Phorum Physicist

    Don't forget that the Nyquist sampling theorem is just that, a theorem.

    From dictionary.com:

    theorem - A proposition that has been or is to be proved on the basis of explicit assumptions.

    This leads us to ask the question, what are the assumptions in the sampling theorem?

    That's easy - the sampling theorem assumes that the amplitude at each sample point is know exactly and that successive samples are taken at intervals of precisely 1/f seconds where f is the sampling frequency.

    Furthermore, it assumes that in converting back to analogue the PAM staircase function exactly represents the samples (ie in both amplitude and time) and that the transform back to the analogue waveform is perfect.

    Now, in practice none of these assumptions can be achieved.

    In my experience 44.1/16 is not capable, in practice, of fully representing full range analogue signals. The effect is subtle but you lose separation and you introduce a certain claustrophobic feeling to the listening experience with 44.1/16.

    In contrast higher resolution digital formats do a much better job of representing analogue signals in my experience.

    There is a far more significant effect from increasing the word length that you neglect to mention. The more bits you use to represent the amplitude at each sample point the more accurate your sample values are in representing the "true" amplitude at that point - and thus the closer to the Nyquist ideal you will be.

    This, in my opinion, is the most significant drawback with the CD format - 16 bits does not allow for enough accuracy in the quantization of the amplitude to be able to reproduce the analogue waveform without an audible difference compared with the input analogue signal.
     
  21. Tetrack

    Tetrack Forum Resident

    Location:
    Scotland, UK.
    If standard CDs reproduce everything perfectly then there would be no need for higher resolution formats. We know the CD format cuts off everything above a certain frequency range that we are supposedly not able to perceive, but the body and it's reactions do not lie.

    I can listen to analog recordings for a few hours and feel the physical effects. The CD format does not reproduce the same effect IME, so something is missing. :confused:
     
  22. OcdMan

    OcdMan Senior Member

    Location:
    Maryland
    To add to that...

    I realize it doesn't mean much in the "real world" but look at, for example, a 10kHz square wave sampled at 44.1/16 and then compare it with one at 192/16. At 44.1 the square wave looks more like a sine wave, nice and round. Increasing the rate to 192kHz produces an actual square-looking wave. A higher sampling rate is clearly good for more than just an extended frequency response, it even helps out within the audible range of sound. So not only do you need more bits, you need more "opportunities" to assign them values.
     
  23. Grant

    Grant Life is a rock, but the radio rolled me!

    Based on my very recent unscientific tests concerning recording at various sampling rates, I can no longer hold this view. I will submit that 44.1k/16-bit is inadequate, and does not capture all of the ambiance. This goes against the Nyquist theorem and any other logic, and i'll gte ridiculed on that "other" website, but I know what I hear. Maybe it had something to do with a converter. I don't know. But, that's what I have found.
     
  24. OcdMan

    OcdMan Senior Member

    Location:
    Maryland
    Count me in. With 44.1/16-bit, there is a lot of approximating going on. Sure, you can capture the frequency response but you just can't pinpoint it down to exactly when and where at that sampling rate/bit depth.

    Of course, I still find CDs perfectly pleasing but the subject of this thread was dealing with perfection.
     
  25. Grant

    Grant Life is a rock, but the radio rolled me!

    Well, we all know the CD ain'r perfect, and hardly anything is. But, some formats get closer than others.

    It's like 16-bit/44.1k gets the fundametals, you know, the essentials of the sound, but not the ambience that gives the sound it's signature, if that makes sense.

    ...oh, I can hear those scientists and clogged ears over "there" laughing that "they just can't make this stuff up"! :laugh:
     
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