Hubub about DACs...

Discussion in 'Archived Threads 2001-2004' started by Randy G, Mar 10, 2002.

  1. Randy G

    Randy G Second Unit

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    >>ALL these units(upcoming pre-pros) will use 24/192 DACs. Why would you get a unit(referring to 24/96) that doesn't offer this obvious sonic advantage
     
  2. RicP

    RicP Screenwriter

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    If they laughed, perhaps I wont be reading any more of their articles.

    Having 24/192 DACs isn't so that we can hear frequencies of 96Khz, it's so that noise shaping can be done at a much higher frequency via oversampling. The more you can push into the inaudble band, the better the resulting analog signal will be from 20Hz - 20 Khz.

    They should have known this.
     
  3. Selden Ball

    Selden Ball Second Unit

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    Randy,

    All other things being equal, it is true that people would not be able to hear any differences as the sampling rate increases above a certain point. Unfortunately, all other things are not equal.

    For example, analog output filters are more easily designed for higher sampling rates. Aliasing is less of a problem. 8x and 16x oversampling used to be common in high quality CD players before digital outputs became popular (and may still be: I haven't paid much attention to that part of the market in recent years). While moving that oversampling into the sample rates of the ADCs and DACs themselves may be overkill, it can't hurt, either.
     
  4. Randy G

    Randy G Second Unit

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    I guess the real question is: Is there an audible(as opposed to measurable) difference? If I sat ya down and put ya thru a double blind(please, don't start flaming because of DB tests) test, would YOU bet your life on your ability to discern a difference? Just curious.
     
  5. Selden Ball

    Selden Ball Second Unit

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    Personally, probably not, all other things being equal. When calibrating my HT recently, I was dismayed to discover that I couldn't hear anything over 15KHz anymore.

    On the other hand, some extremely inexpensive receivers are advertised as having very high sampling rates. I suspect the limitations in their audio quality will be quite audible due to other compromises in their designs.
     
  6. Randy G

    Randy G Second Unit

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    Agreed...and its probably in the amp section.
    I guess I just find it humorous how so many people get hung up on such insignificant minutia when other things in the feature set can have so much more of an impact on their sonic enjoyment...like bass management, amp capability, user interface, perhaps DPL II etc., etc.
     
  7. Lewis Besze

    Lewis Besze Producer

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    Randy,I agree with those guys as well,however as Ric P commented this is more of compatibilty issue from a technical standpoint,but from a pracrical one how much higher they wanna take their noiseshaping,which is why the laugh IMO.
    The sad fact is that the current high end DAC's claim 24 bit resolution but they struggle with a near 20bit,which makes you wonder what these DAC "hypers" talking about.
    I think if ever reach a TRUE 24 bit resolution,then we'll be just fine[at least for awhile][​IMG].
     
  8. RobertR

    RobertR Lead Actor

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  9. AntonS

    AntonS Stunt Coordinator

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    Just for the sake of clarification. A 24-bit digital sample theoretically gives

    20 * log10( 2 ** 24 ) = 144dB S/N ratio.

    Practically no analog circuit comes even close to that, but having more bits still allows to have more bits for the singal itself. So if a spec on some equipment says 108dB S/N ratio (which is very not bad), that means that they utilize 18 bits and discard 6 bits of noise.
     
  10. Randy G

    Randy G Second Unit

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    Hey, if we can be convinced that 24/192 is absolutely necessary for true sonic fidelity, then the content providers won't have to fill up all that disc space with music....an excellent ploy.
    Personally, I believe that 20/96 is more than good enough...unless we're talking about archival purposes.
    ps-the preceding announcement was brought to you by my opinion, and worth exactly what you paid for it.
     
  11. Saurav

    Saurav Cinematographer

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    What about doing math and/or calculations on those samples? Doesn't it help to have an extra bit or two at the end so that whatever processing is done on that data doesn't cause rounding off errors in the audible bits? That's the only reason I can see for ever wanting more bits... 144dB SNR is insane.
     
  12. Lewis Besze

    Lewis Besze Producer

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  13. Earl Simpson

    Earl Simpson Supporting Actor

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    Even when I was very young, I could not hear anything past 17,800 cycles. I am afraid to check these days. I think dogs could be used to check this out for us. If you have a flat clean signal to 15,000 cycles, I doubt if you could hear the difference other than the quality of the components in the build. That can have a dramatic affect on sound. I hand built an amp when I was very/very young.When I was finished I played the unit for 30 days and then went in a R&Red all the capacitors with oversized good stuff where appropriate. It not only sounded better, my dad who is tone deaf could hear the difference.
     

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