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Why would 24 bit / 192 khz flac sound any better than 16 bit / 44.1 khz flac if both are lossless (if at all)?

Discussion in 'Sound Science' started by thesuperguy, Mar 15, 2014.
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  1. drtechno
    basic audio theory don't cover programs. and the theory of 16 extra bits of thermal noise is flawed. but the 40 bit is unpublished info I got from a protools daw programmer that programmed may daws besides protools.
    that part doesn't matter. but if you really want to know about value spacifics , A 64-bit engine is technically not better than a 32-bit engine for summing.

    A 32-bit engine does all calculations on the fpu, thereby using registers that can be as large as 80 bit. (The accumulator even extends this)
    A 64-bit engine has no other choice than using SSE instructions, of which the registers are limited to 64 bit strings. Some people will argue that SSE strings are 128 bit, but that's incorrect. The 128 bit string is split up in two 64 bit strings.

    So, if well written, a 32-bit audio engine can be more precise than a 64 bit engine, since it can hold larger strings of numbers.
    That is when the numbers are kept as long as possibly can in the registers and are brought back to 32-bit as less as possible.
    On the other hand, 64-bit is more precise than 32-bit thereby avoiding any rounding errors. But these rounding errors are neglectable when it comes to adding and subtracting numbers, which is what a summing engine basically does.
    Rounding and additive (cumulative) errors are important for any process where DSP is concerned, but all DAW and plugin manufacturers are already using double precision for most -if not all- of their critical calculations.

    In practice 32 bits vs. 64 bit will make no difference at all, unless you are really abusing the audio engine and are burning every gain stage by dozens of dB's and/or in scientific tests set up to expose the problem. In every day use (read: proper use) there shouldn't be any difference.

    In other words, if you can hear (and measure) the difference between a 32-but engine and a 64-bit engine, then something is/was wrong (badly designed) with the 32-bit engine to start with.
    In a properly build DAW, the numbers are not stored in 32-bit strings, but kept in the FPU registers as long as possibly can before they are dumped (and rounded) to a 32-bit string. Thereby the intermediate roundings (80 bits =>32 bits) are much less frequent, than when using SSE strings which need to be dumped as soon as the 64bit strings are "full".
    Of course, depending on the internal structure of each an every DAW -and the way things are tested- there are arguments in favor of both techniques. All I said is that in normal, proper, non-abusive use, the (rounding) error in a 32-bit mixer will remain in the LSB's, exactly as in a 64bit mixer.
    some other fun facts:
    8-bit = 256 Dec.
    100000000 Bin.
    Dynamic Range = 48.16dB
    16-bit = 65536 Dec.
    10000000000000000 Bin.
    Dynamic Range = 96.32dB
    20-Bit = 1048576 Dec.
    100000000000000000000 Bin.
    Dynamic Range = 120.4dB
    24-Bit = 16777216 Dec.
    1000000000000000000000000 Bin.
    Dynamic Range = 144.48dB
    32-Bit = 4294967296 Dec.
    100000000000000000000000000000000 Bin.
    Dynamic Range = 192.64dB
    64-Bit = 18446744073709551616 Dec.
    10000000000000000000000000000000000000000000000000000000000000000 Bin.
    Dynamic Range = 385.28dB
  2. gregorio
    You asked for and received evidence that your statements were false. I've asked for you to provide evidence to support your statements but your only response is just to make up more ridiculous "facts", more ridiculous even than the "facts" you've already made up! If digging a deeper hole for yourself is in fact what you're trying to achieve, then you're doing an excellent job.
    Back up your statements with some corroborating evidence. Put up or shut up!!
    Ruben123 likes this.
  3. drtechno
    interesting. since I copied and pasted that reply from a different forum.
    because I couldn't said it better myself.
    In my opinion,  the 16 bit extra noise theory you have is flawed.
    do you have some findings to show to back up this theory?
  4. gregorio
    1. I didn't ask for a link to one side of another argument on another forum from unattributed amateurs, students or newbies, I asked for supporting evidence, which you have still not supplied! do you know what "evidence" is? That hole is just getting deeper!
    2. You've already demonstrated a willingness to just make up "facts", so why should your opinion be anything other than worthless, unless you can convincingly corroborate it? That's going to be a very tall order though as it flies in the face of the known science. You do realise this is the science forum?!
    3. You can look up Johnson Noise for yourself. You refuse to back-up any of your laughable theories (#2) but you're asking for even more evidence from me, to back up knowledge which any experienced audio engineer should already know anyway! Surely that hole is deep enough already?
    BTW, your added/edited bits:
    1. "but the 40 bit is unpublished info I got from a protools daw programmer that programmed may daws besides protools." - So now you're progressing beyond just making stuff up to making up attributions for the stuff you're making up! I've personally known a number of Pro Tools programmers, including two heads of program development. Pro Tools has never been 40bit and has never even planned a 40bit architecture, prove otherwise!
    2. "In practice 32 bits vs. 64 bit will make no difference at all, unless you are really abusing the audio engine and are burning every gain stage by dozens of dB's and/or in scientific tests set up to expose the problem. In every day use (read: proper use) there shouldn't be any difference." - That's not necessarily true, which you'd know if you were an audio engineer! There are applications where it could make a difference, film mixing for example, where up to 1,000 or so channels of audio are being mixed.
    3. Even if we accept that 32bit is indistinguishable from 64bit when mixing (which it is in music), how does that support your argument? What has mixing environments got to do with distribution formats and what benefit would there be to a 40bit distribution format? When I asked for supporting evidence, I meant evidence to support your argument, not mine!
    4. What has the dynamic range of 32bit or 64bit fixed (integer) got to do with anything? It's not connected to your assertions on mix environments and it's certainly not recordable or reproducible. Maybe you're confusing float and integer bit depths? Which is not something an experienced audio engineer would do!
    Again, some actual evidence please. I'll change the choice to something more applicable: Put up, shut up or appear to be an idiot!
  5. Arpiben
    For those interested and not to bring more agitation or thermal noise to the actual debate.

    Thermal noise or Johnson - Nyquist noise as a value of: - 131 dBm at room temperature & with 20kHz bandwidth.
    Something in between 21/22 bits in digital coding.
    sonitus mirus and castleofargh like this.
  6. gregorio
    I think the exact value of the noise would depend on the exact construction/components of the individual ADC, although your figure does appear quite reasonable/representative. In practical implementation, I can't think of any pro ADCs off the top of my head which actually achieve 21bits, although several achieve between 20 and 21bits.
  7. castleofargh Contributor
    I see that as a best case scenario, where a great many other noises can come over it. it's significant of what can be achieved as a limit. I don't imagine some 100% superconductor ADC in liquid nitrogen to be sold anytime soon. ^_^
  8. Arpiben
    As far as I remember, you are right;
    1. there are other noises` contribution: Shot Noise, Flicker Noise, etc...
    2. the theoritical value depends on ADC`s types/components.
    Regarding the Effective Number Of Bits it can be aproximated by:
    where SINAD: Signal to (Noise Adding Distorsion) Ratio
    when dealing with sine wave.
    Forgetting maths,my purpose when I posted a typical thermal noise value was more for giving an idea of one of the analog domain`s limitation.
    In digital domain, some DAC manufacturers are providing  Noise Floor values around -300 dB or FFT Jitter around -180 dB.
    Therefore, I admit that it is sometimes easy to mix both domains and forget the limitations of analog one [​IMG] 
  9. drtechno
    well the thermal noise is not really a big player in the noise generated by the ADC its the noise generated by the shift register mixing the resistor network value and the clock signal. This noise is a major variable in the overall quantization noise, and it has a name call spious noise. Granted most of this noise is supposed to be suppressed by the input circuit. But like all filter circuits. they are never perfect. That is why certification authorities measure the  amount of this type of rf leakage coming out from the input of a converter.
  10. castleofargh Contributor
    I removed the last few posts, TOS doesn't allow personal attacks.
  11. gregorio
    Fair enough, it was getting a bit over heated. Lets do this properly then:
    Clock signal error and the noise it generates is not called spurious noise, it's called "jitter noise". A good professional ADC will have jitter in the few tens of pico second range and produce jitter noise down around the LSB or in some cases even lower. Below is the jitter spectrum of the roughly decade old Prism Orpheus, showing it's jitter noise (with a 1kHz input signal) is below -140sBFS, which is several times lower in level than the thermal noise and therefore NOT a major variable or "player" relative to thermal noise!
    (Hugh Robjohns, 2010. "Does Your Studio Need A Digital Master Clock?", SoundonSound.)
    Being the science forum, if you are going to make statements of fact or refute the statements of others, you MUST back up your arguments with some convincing evidence, otherwise it will be viewed as nothing more than the made-up nonsense of a shill or troll. Posting deliberately made-up nonsense is an insult to this forum, it's guests and members. In order to receive politeness and respect here, you must obviously treat this forum and it's members with politeness and respect, NOT with contempt!!!
  12. Arpiben
    castleofargh likes this.
  13. drtechno
    Thanks for the post Arpiben. Yes clocking  is very important as that was drilled into my head by Mr. Ludwig and Mr. Williams about 20 years ago to use an external clock.
  14. nick_charles Contributor
    Dunn's papers are very informative and definitely worth reading, the only thing that his and Hawksford's (also highly readable) papers lack is that, they do not address audibility of jitter except as a mathematical model based on rather extreme sound pressure levels. To date we have little (well none really)  empirical evidence that jitter as found in semi-competent digital components is actually audible, of course that does not stop a cottage industry in jitter reducers....
  15. spruce music

    I'll repeat the link from gregario's post.

    Rethink that external clock idea. 
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