DOP vs PCM

Discussion in 'Sound Science' started by endgame, Sep 16, 2017.

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DOP or PCM?

  1. DOP

    25.0%
  2. PCM

    75.0%
  1. 71 dB
    For the most part I agree with this.

    We can record and reproduce signals. Signals have properties such as amplitude, frequency, spectrum, decays time, phase etc.

    Standards behind measurements are often children of their time. At some point audio technology might develop to a new level and new standards are needed.
     
    endgame likes this.
  2. endgame
    This is a good explanation. Thank you.
     
  3. pinnahertz
    All aspects of any wave can be captured and crunched into the above (and much more) with a single measurement that captures enough data for the original to be reconstructed. In fact that is the basis of all modern audio measurements.
    No, that's backwards. There are no standards behind measurements, there are standards based on measurements, but frankly when it comes to things like FR, THD and noise (you know, the audible stuff), there are no standards other than those of a specific application. When measured, they form figures of merit, typically reduced to simple single figures so they are easy to assimilate, but relatively meaningless (in terms of audibility) when they should be presented at least as 2 dimensional graphs if not 3d graphs.

    THD for example is shown as a single figure. The, as an elaboration, expressed as a quantity vs frequency. Neither represents a degree of audible effect, which is a function of THD specific spectrum vs amplitude vs time in the presence of a masking signal. Nothing wrong with the measurements, though, they are dead-nuts on. Interpretation is hobbled by the need to simplify.

    Please don't confuse measurement with specifications and standards, and don't confuse presentation of specs with anything that correlates to audibility. There IS correlation, but not when reduced for simplicity.
     
  4. bigshot
    If you look at the history of recorded sound as it relates to measurements, you'll find that most of the major standard measurements have been known about since the 1920s at Bell Labs. The technology of how to electronically do it has changed, but the physics of sound is very well understood. We've gotten to the point where our ability to record and play back are audibly perfect. ABX testing has proven that. We've also extended our ability to measure far beyond our ability to hear. If there's anything new to be added at this point, it's going to be in the way the technology is applied... recording techniques, signal processing, playback with multiple channels, etc... not in the way the fundamental principles of sound are measured. And as these new ways of recording, signal processing and playback are implemented, the concept of some sort of audible distortion of the sound being a bad thing will be replaced by using manipulation of the signal to improve sound.
     
    Last edited: Sep 19, 2017
  5. castleofargh Contributor
    new measurements or standards can always helps for specific things we wish to define, as in finding a new way to describe a specific variable, or struggling to make a fine crossover between physical sound and somebody's interpretation of it. mostly because we don't have a mind reader or the complete 3D scan of the listener. those issues have nothing to do with sound as a signal or as a physical wave.
    but that's missing the point anyway. we can't be fine describing the entirety of a song in a simple 2 axis graph, 1 amplitude changing over time (X2 for stereo), and then pretend like that very signal is something super complicated we don't know how to characterize or measure. this is paradoxical.
     
  6. 71 dB
    Impulse response describes fully a linear system, so yes (assuming the system is linear enough).
     
  7. TYATYA


    Yes, you said my mean ! There are difference in low range. Solid impact, quick cut off (less decay), detail. Those are a bit melting down on wav multichanel
     
  8. gregorio
    The difficulty for many audiophiles so often comes down to an inability to understand or accept human perception. In English and most modern languages we have words which equate to sound, music and noise. The last two however are words used to describe what is a purely human perception/preference and are not things which actually exist. Therefore any discussion or description of music must be based on human perception. This is hardly a new development or point of only scientific interest, it's been a topic of considerable debate amongst those seriously interested in music for a couple of centuries, a debate which spills into the much wider general public occasionally. So how can some/many audiophiles not be aware of this? The only logical answer is that they have little interest in or understanding of music, despite statements to the contrary. Their interest and knowledge is in their perception/preference of audio reproduction equipment, not the audio itself (or it's "fidelity") and therefore these audiophiles are not, by definition, audiophiles. Paradoxical indeed!

    Sorry, I've no idea what you are trying to say.

    G
     
  9. bigshot
    Music is organized sound. Noise is disorganized sound.
     
  10. gregorio
    That's a quite common definition of music which originates from Edgard Varese.but, while it works as a good explanation of his compositional goals it doesn't work as a definition of music. If it were true, then normal speech would be music, so would the sound of most car engines but an entire musical movement would not be music (Indeterminacy/Aleatoric) and neither would many/most of the compositions of a number of the C20th greatest composers (Cage, et al). Of all the attempts at a simple definition of music, I like Berio's the best: “Music is everything that one listens to with the intention of listening to music”.

    G.
     
  11. 71 dB
    A lot of people would say a lot of my favorite music is noise. I guess the concept of something being organized is subjective...
     
  12. RRod
    Perhaps he meant DTS core vs. the DTS-HD MA version, converted to WAV? I've never seen DTS and a true-blue 5.1 WAV track on the same disc.

    Also, when comparing DTS to AC-3 one has to make sure that he has the default dynamic range compression off on the AC-3.
     
  13. bigshot
    Normal speech can be music if it's Shakespeare sonnets. But most people don't make much effort to organize their words.
     
  14. Strangelove424
    Shakespeare's a good example, as he usually wrote in iambic pentameter. I think some car engines are pretty musical too. I roll my windows down when certain cars pass by. And manufacturers tune engine and exhaust notes to create identifiable, often brand specific tones.

     
  15. pinnahertz
    Doesn't matter, the comparison is invalid and impossible because of potential changes in mastering.
     

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