sampo started this thread as OP so not sure what this discussion is about, i think he was talking about 'subtractive' dither. i actually think the problem is more nuanced, perhaps a music business problem dealing with music publishing and licensing law
On Mon, Jan 10, 2022 at 12:55 PM vicki melchior <[email protected]> wrote: > Eric, > > You’ve lost me. I don’t follow what you are worrying about. This > discussion isn’t about the audibility of dither. In fact white noise > generally is fairly benign from an audibility standpoint. > > The reasons dither is added have to do with avoidance of distortion due to > undithered quantization error, It is this distortion that can be quite > audible and can produce coloration, because the distortion is coherent in > nature and not noiselike. > > Vicki > > On Jan 10, 2022, at 12:33 PM, Zhiguang Zhang <[email protected]> wrote: > > well i'm not here to talk about whether or not i can discriminate dither > from music, it is pointless for me as someone who listens to music > > On Mon, Jan 10, 2022 at 12:31 PM vicki melchior <[email protected]> > wrote: > >> No, I never said that dither becomes a coherent signal. Dither is noise. >> >> >> >> On Jan 10, 2022, at 12:14 PM, Zhiguang Zhang <[email protected]> wrote: >> >> Vicki, >> >> that is rather incredible to me if true, that dither is detectable as a >> coherent signal but i suppose that the dither that i was referring to is >> *necessarily* a part of the program material signal because it is the >> dither that has already been added during the recording chain and thus not >> a separate coherent signal >> >> https://ask.audio/articles/the-how-and-why-of-dithering-in-pro-tools >> >> On Mon, Jan 10, 2022 at 9:15 AM vicki melchior <[email protected]> >> wrote: >> >>> Eric, I’m not sure I get the gist of your question, but “hearing into >>> the noise” refers to the fact that coherent signals can be detected at some >>> level (around 10-15 dB) below the RMS level of the noise (whether the noise >>> is dither or part of the signal). The mathematical analogy for this is >>> coherent/noncoherent gain; the hearing system integrates both noise and >>> signal over the bandwidth of the particular cochlear filter. Noise >>> integrates non-coherently while signal integrates coherently, leaving a net >>> gain in SNR. This is relevant for a number of reasons. First, you can >>> (maybe) detect actual signal at those depths below noise. But second, you >>> can also hear distortion lying well below the noise floor if it is >>> relatively coherent, especially the peaks associated with truncation >>> distortion when dither has been omitted. These arguments are highly >>> relevant to determining the bit depth needed to convey program material, >>> and that in turn, is a function of the dynamic range audible to humans >>> along with an understanding of the noise sources present in the given >>> system. So it is not about hearing the noise, but rather hearing signal >>> below the noise floor. >>> >>> >>> On Jan 9, 2022, at 8:10 PM, Zhiguang Zhang <[email protected]> wrote: >>> >>> not sure if this point is important, but the dither that is added before >>> you hear the program material being reproduced isn't actually supposed to >>> be 'heard' - so this argument doesn't appear to make much sense in my >>> mind. engineers might hear the dither when they're familiar with the >>> studio that they work in, but past that, i'm not sure i get the point of >>> discussing the practical limits of hearing something added which, for all >>> intents and purposes, is hidden. it's almost like you're trying to reverse >>> engineer what recording interface an audio engineer was using >>> >>> On Sun, Jan 9, 2022 at 5:48 PM Brian Willoughby <[email protected]> >>> wrote: >>> >>>> Thank you for these titles. I've already found them in the AES library. >>>> >>>> Brian Willoughby >>>> >>>> >>>> On Jan 9, 2022, at 13:43, vicki melchior <[email protected]> >>>> wrote: >>>> > As far as measurements of how far “into the noise” we can hear, there >>>> aren’t a lot of good published numbers that I know of (having reviewed the >>>> subject a couple of years ago), but Bob Stuart and Peter Craven argue >>>> dynamic range and, to a certain extent, audibility below the noise floor in >>>> a couple of papers published in JAES in 2019. They are based on >>>> psychoacoustic arguments as well as listening test results, the latter as >>>> part of their studio and lab work on MQA. If interested, their (open >>>> access) papers are in the AES e-lib, “The Gentle Art of Dithering” and “A >>>> Hierarchical Approach for Audio Capture, Archive and Distribution”. >>>> >>> >>> >> >
