24bit vs 16bit, the myth exploded!

Discussion in 'Sound Science' started by gregorio, Mar 19, 2009.
  1. TheSonicTruth

    And what does he mean by "wrong guy"?
  2. castleofargh Contributor
    you, I mean you of course. you're the one who came arguing against dynamic compression with the DR meter while giving a wrong explanation of what it does. the post right after cleared everything there was to clear, but it still took many more to get you to just consider that maybe you needed another tool.
    and yet, here we are. you clearly comparing the dynamic of a orchestra IRL, and a DR meter number on CDs. making me feel that you haven't listened to anything we discussed about the DR meter tool just a few days ago.
    Damn it! You can have FLAC the size of MP3! Freaking EPIC!!!
    Oh wait. Sometimes you get artifacting ("herding_calls" sample) :frowning2: but not on brickwalled audio.
    Yeah, I hear some noise on Daft Punk - Instant Crush. That "gangam style" is way too brickwalled and thus fraudy.
    Upd. Using dithering can fix that noise :) though it occupies ~100 Kbps more. Still the noise can be an audiocassette fetish for some.
    Last edited: Nov 12, 2017
  4. amirm
    Sorry for going back to the first post in this thread. I just got here :). But turns out we can absolutely do that. Noise in your recording comes from your speakers, i.e. point source. Noise that is in the environment in your room is diffused all around you. Putting aside the important bit that the spectrum of noise in our living room is anything but "white" (it is heavily biased towards low frequencies because walls and doors don't filter it as much), our hearing system is capable of distinguishing between point noise sources and diffused one. Think of the ancient man needing to hear a dangerous animal coming at them, making noises, over the noise of the environment. With two ears and a brain, we can distinguish between them because what each ear hears is different and that differential lets us identify the noise and its direction.

    This has been researched with controlled testing and published in the Journal of Audio Engineering Society: Dynamic-Range Issues in the Modern Digital Audio Environment, ” Fielder, Louis D., JAES Volume 43 Issue 5 pp. 322-339; May 1995


    So in summary, listeners could detect white noise coming out of speakers at levels ranging from minus 2 to plus 9 db SPL whereas the environmental noise was at 20 to 35 dbA SPL.

    This also undermines the thesis of the original post of taking average room noise SPL, adding it to CD dynamic range and such to say we don't need that kind of dynamic range. That math may make sense in our stomach, but it does not when you look at the science of it (for more see https://audiosciencereview.com/forum/index.php?threads/dynamic-range-how-quiet-is-quiet.14/).
  5. bigshot
    A listening room with a 20 to 30dB noise floor is quieter than any listening room in a home. That's like a recording booth, not a listening room.
  6. castleofargh Contributor
    while I agree that simply adding the noise of the room to the music's dynamic is an oversimplified idea. countering it with audibility measured for white noise where the room's own noise floor is now the loudest signal, that's IMO even more inadequate to depict realistic listening or listening needs.
    sure enough noise isn't some opaque paint spread over the stuff below, but masking is still very much a reality, so is the human's limited instantaneous dynamic range.
  7. bigshot
    The easiest way to tell how much dynamic range is enough is to sit in your living room, put on a CD and turn the volume up to the loudest comfortable volume and listen to see if you hear the noise floor of the CD. (hint: you won't)
  8. csglinux
    One day, with the right equipment, and the right recording, and an appropriate period of (what should be) silence in the recording, you might.

    I posted a link a while back to a video interview with Rob Watts where he claims noise shapers at -130, -140 dB made an audible difference. He thinks subtle cues from the multiple reverberations in a large cathedral were responsible for the improved depth perception of a pipe organ recording. Now, I've not heard those demos myself, so maybe all this is just marketing. I'm all for a healthy dose of skepticism. Is there another plausible explanation?
  9. RRod
    With my PM-3s on, which have pretty good isolation in the meaty audible range, I could hear white noise with -110dBFS peak / -114 dBFS RMS pretty readily in my not too-too quiet work environment. This is with the pot set for the highest I set it for music. Any actual sound of course swamps it immediately, including the piped-in white noise for work ^_^
    Last edited: Nov 13, 2017
  10. castleofargh Contributor
    the most plausible explanation without some hyper specific conditions, would be that he's wrong, obviously.
    maybe you can abuse noise shaping at -130dB and move it all to some high level energy in the ultrasounds. rand maybe then because of a different issue and bad filtering you can end up making some audible IMD or whatever. maybe what he calls -130dB is in fact a loud signal on some totally silent track with the loudest stuff already at -70dB? IDK what he tested, or how, or what else he measured before deciding that it was fine to suggest some silly hypothesis.
    in short, the claim needs information about the test related to it. else it means nothing at all. and the hypothesis is only that, no reason to take it more seriously than any other idea anybody else could have.
  11. csglinux
    Except something like this could be easily disputed by anybody else doing the same listening tests. I may be wrong, but I doubt Rob would throw his (fairly considerable) reputation under the bus like that.
  12. bigshot
    Anything can happen in theory. But in practice, I think saying that I would never need more than 16 bits is a VERY safe bet. I've had CDs for decades and I haven't run into that sort of situation yet.
    HAWX likes this.
  13. csglinux
    The question is - how much better can recorded music playback possibly get? We won't know until we get there, but we still seem to be making incremental improvements, even when the specs say we shouldn't be able to hear a difference. E.g., look at the specs of a Chord Hugo 2. Then go A/B it with a Chord Dave. There's something going on there I don't understand.
  14. bigshot
    Equipment can be improved infinitely I suppose. But human ears aren't likely to evolve to be able to hear better in our lifetimes. Since digital audio is capable of perfectly reproducing sound for human ears, we're sitting smack dab in the middle of audio nirvana. But there are still going to be people who think they need better than that.
  15. csglinux
    Leaving aside the obvious improvements in speakers and headphones, have you not experienced any improvement at all in DACs and amps in recent years? Maybe we should have, but it doesn't feel like we've hit the wall yet. At least, an awful lot of folks on headfi don't think so. Are we all suckers?! :wink:

    I'm probably getting off-topic. These improvements are most likely nothing to do with bit depth. They may even have nothing to do with sample rate or timing - I suspect there are far worse crimes being committed by the internals of the electronic circuitry. But, I've often wondered if - one day, with the perfect recording - how nice it would be to crank the volume all the way up in a very quiet/silent passage and still not hear any noise floor.

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