Funny, Andy, I was thinking about the merits of mono versus stereo dither a couple of nights ago while having dinner…while independent dither makes sense, in that your equipment’s background noise should be uncorrelated, there is the issue with headphones (maybe making it more obvious, more spacious?)…I didn’t think it through very far, just a thought to try out, but it’s interesting that you should bring it up...
But actually, those files aren’t using my plug-in. Since the test didn’t require a constant residual level at various truncation levels (which is the best part of the plug-in—nothing like juggling a couple of gain plug-ins to manually compensate the gain in a null test, and blasting your ears off when a stray index finger mouse-scrolls bit-depth down to one or two bits with a high gain setting in place), I went with the off-the-shelf stuff, and not have a chance that someone would question whether my plug-in was doing something misleading. DP’s Quan Jr plug-in is supplying the dither. I can mod my plug-in for mono dither, though, and supply a version of that. You make an interesting observation, thanks. > On Feb 5, 2015, at 6:31 PM, Andrew Simper <a...@cytomic.com> wrote: > > Hi Nigel, > > Can I please ask a favour? Can you please add a "mono noise" button to > your dither plugin? In headphones the sudden onset of stereo hiss of > the dither is pretty obvious and a little distracting in this example. > I had a listen with a "make mono" plugin and the results were much > less obvious between the 16-bit with dither and the float file. It > would be interesting to hear a stereo source (eg the same Diva sounds > but in unison) put through mono noise dithering. > > The differences are pretty clear to me, thanks for posting the files! My > setup: > > (*) Switching between files randomly the three files randomly playing > them back with unity gain (the float file padded -6 dB to have the > same volume as the others) > (*) FireFace UCX with headphone output set to -12 dB, all other gains at unity > (*) Senheisser Amperior HD25 headphones > > My results > > (*) the float file is easy to spot, because of the differences when > compared to the other two > (*) the dithered one sounds hissy straight away when I switch to it, > it is obvious that the hiss is stereo, my ears immediately hear that > stereo difference, but otherwise it sounds like the original float > file > (*) the undithered one, right from the start, sounds like a harsher > version of the float one with just a hint of noise as well, an > aggressive subtle edge to the tone which just isn't in the original. > When the fadeout comes then it becomes more obvious aliasing > distortion that everyone is used to hearing. > > I also tried boosting the float version of the bass tone to -1 dB (so > another 18 dB up from with the same test setup), it was loud, but not > anywhere near the threshold of pain for me. I then boosted it another > 12 dB on the headphone control (so 0 dB gain), so now 30 dB gain in > total and my headphones were really shaking, this was a bit silly a > level, but still definitely not painful to listen to. My point being > that this is a very reasonable test signal to listen to, and it is > clear to hear the differences even at low levels of gain. > > If I had to choose, between the two 16-bit ones I would prefer the one > with dither but put through a "make mono" plugin, as this sounded the > closest to the float version. > > All the best, > > Andy > > -- cytomic -- sound music software -- > > > On 5 February 2015 at 16:46, Nigel Redmon <earle...@earlevel.com> wrote: >> Hmm, I thought that would let you save the page source (wave file)…Safari >> creates the file of the appropriate name and type, but it stays at 0 >> bytes…OK, I put up and index page—do the usual right-click to save the field >> to disk if you need to access the files directly: >> >> http://earlevel.com/temp/music-dsp/ >> >> >>> On Feb 5, 2015, at 12:13 AM, Nigel Redmon <earle...@earlevel.com> wrote: >>> >>> OK, here’s my new piece, I call it Diva bass—to satisfy your request for me >>> to make something with truncation distortion apparent. (If it bother you >>> that my piece is one note, imagine that this is just the last note of a >>> longer piece.) >>> >>> I spent maybe 30 seconds getting the sound—opened Diva (default “minimoog” >>> modules), turn the mixer knobs down except for VCO 1, set range to 32’, >>> waveform to triangle, max release on the VCA envelope. >>> >>> In 32-bit float glory: >>> >>> http://earlevel.com/temp/music-dsp/Diva%20bass%2032-bit%20float.wav >>> >>> Truncated to 16-bit, no dither (Quan Jr plug-in, Digital Performer), saved >>> to 16-bit wave file: >>> >>> http://earlevel.com/temp/music-dsp/Diva%20bass%2016-bit%20truncated.wav >>> >>> You’ll have to turn your sound system up, not insanely loud, but loud. (I >>> said that this would be the case before.) I can hear it, and I know >>> engineers who monitor much louder, routinely, than I’m monitoring to hear >>> this. My Equator Q10s are not terribly high powered, and I’m not adding any >>> other gain ahead of them in order to boost the quiet part. >>> >>> If you want to hear the residual easily (32-bit version inverted, summed >>> with 16-bit truncated, the result with +40 dB gain via Trim plug-in): >>> >>> http://earlevel.com/temp/music-dsp/Diva%20bass%2016-bit%20truncated%20residual%20+40dB.wav >>> >>> I don’t expect the 16-bit truncated version to bother you, but it does >>> bother some audio engineers. Here's 16-bit dithered version, for >>> completeness, so that you can decide if the added noise floor bothers you: >>> >>> http://earlevel.com/temp/music-dsp/Diva%20bass%2016-bit%20dithered.wav >>> >>> >>> >>>> On Feb 4, 2015, at 1:10 PM, Didier Dambrin <di...@skynet.be> wrote: >>>> >>>> Yes, I disagree with the "always". "Not always needed" means "it's >>>> sometimes needed", my point is that it's never needed, until proven >>>> otherwise. Your video proves that sometimes it's not needed, but not that >>>> sometimes it's needed. >>>> >>>> >>>> >>>> -----Message d'origine----- From: Nigel Redmon >>>> Sent: Wednesday, February 04, 2015 6:51 PM >>>> To: A discussion list for music-related DSP >>>> Subject: Re: [music-dsp] Dither video and articles >>>> >>>>> I totally understood the point of your video, that dithering to 16bit >>>>> isn't always needed - but that's what I disagree with. >>>> >>>> Sorry, Didier, I’m confused now. I took from your previous message that >>>> you feel 16-bit doesn’t need to be dithered ("dithering to 16bit will >>>> never make any audible difference”). Here you say that you disagree with >>>> "dithering to 16bit isn't always needed”. In fact, you are saying that >>>> it’s never needed—you disagree because “isn’t always needed” implies that >>>> it is sometimes needed—correct? >>>> >>>> >>>>> On Feb 4, 2015, at 5:06 AM, Didier Dambrin <di...@skynet.be> wrote: >>>>> >>>>>>> Then, it’s no-win situation, because I could EASILY manufacture a bit >>>>>>> of music that had significant truncation distortion at 16-bit. >>>>> >>>>> Please do, I would really like to hear it. >>>>> >>>>> I have never heard truncation noise at 16bit, other than by playing with >>>>> levels in a such a way that the peaking parts of the rest of the sound >>>>> would destroy your ears or be very unpleasant at best. (you say 12dB, >>>>> it's already a lot) >>>>> >>>>> I totally understood the point of your video, that dithering to 16bit >>>>> isn't always needed - but that's what I disagree with. >>>>> >>>>> >>>>> >>>>> -----Message d'origine----- From: Nigel Redmon >>>>> Sent: Wednesday, February 04, 2015 10:59 AM >>>>> To: A discussion list for music-related DSP >>>>> Subject: Re: [music-dsp] Dither video and articles >>>>> >>>>> Hi Didier—You seem to find contradictions in my choices because you are >>>>> making the wrong assumptions about what I’m showing and saying. >>>>> >>>>> First, I’m not steadfast that 16-bit dither is always needed—and in fact >>>>> the point of the video was that I was showing you (the viewers) how you >>>>> can judge it objectively for yourself (and decide whether you want to >>>>> dither). This is a much better way that the usual that I hear from >>>>> people, who often listen to the dithered and non-dithered results, and >>>>> talk about the "soundstage collapsing" without dither, “brittle” versus >>>>> “transparent" , etc. >>>>> >>>>> But if I’m to give you a rule of thumb, a practical bit of advice that >>>>> you can apply without concern that you might be doing something wrong in >>>>> a given circumstance, that advice is “always dither 16-bit reductions”. >>>>> First, I suspect that it’s below the existing noise floor of most music >>>>> (even so, things like slow fades of the master fader might override that, >>>>> for that point in time). Still, it’s not hard to manufacture something >>>>> musical that subject to bad truncation distortion—a naked, low frequency, >>>>> low-haromic-content sound (a synthetic bass or floor tom perhaps). >>>>> Anyway, at worst case, you’ve added white noise that you are unlikely to >>>>> hear—and if you do, so what? If broadband noise below -90 dB were a >>>>> deal-breaker in recorded music, there wouldn’t be any recorded music. >>>>> Yeah, truncation distortion at 16-bits is an edge case, but the cost to >>>>> remove it is almost nothing. >>>>> >>>>> You say that we can’t perceive quantization above 14-bit, but of course >>>>> we can. If you can perceive it at 14-bit in a given circumstance, and >>>>> it’s an extended low-level passage, you can easily raise the volume >>>>> control another 12 dB and be in the same situation at 16-bit. Granted, >>>>> it’s most likely that the recording engineer hears it and not the >>>>> end-listener, but who is this video aimed at if not the recording >>>>> engineer? He’s the one making the choice of whether to dither. >>>>> >>>>> Specifically: >>>>>> ..then why not use a piece of audio that does prove the point, instead? >>>>>> I know why, it's because you can’t... >>>>> >>>>> First, I would have to use my own music (because I don’t own 32-bit float >>>>> versions of other peoples’ music, even if I thought it was fair use to of >>>>> copyrighted material). Then, it’s no-win situation, because I could >>>>> EASILY manufacture a bit of music that had significant truncation >>>>> distortion at 16-bit. I only need to fire up one of my soft synths, and >>>>> ring out some dull bell tones and bass sounds. Then people would accuse >>>>> me of fitting the data to the theory, and this isn’t typical music made >>>>> in a typical high-end study by a professional engineer. And my video >>>>> would be 20 minutes long because I’m not looking at a 40-second bit of >>>>> music any more. Instead, I clearly explained my choice, and it proved to >>>>> be a pretty good one, and probably fairly typical at 16-bit, wouldn’t you >>>>> agree? As I mentioned at the end of the video, the plan is to further >>>>> examine some high-resolution music that a Grammy award-winning engineer >>>>> and producer friend of mine has said he will provide. >>>>> >>>>>> ...and dithering to 16bit will never make any audible difference. >>>>> >>>>> If you mean “never make any audible difference” in the sense that it >>>>> won’t matter one bit to sales or musical enjoyment, I agree. I imagine >>>>> photographers make fixes and color tweaks that will never be noticed in >>>>> the magazine or webpage that the photo will end up in either. But I >>>>> guarantee you, there are lots of audio engineers that will not let that >>>>> practically (using the word in the original “practical" sense–don’t read >>>>> as “almost") un-hearable zipper in the fade go. If they know it’s there, >>>>> and in some cases they CAN actually hear it, with the volume cranked, you >>>>> can tell them all day and all night that they are wasting there time >>>>> dithering, because listeners will never hear it, but they will want to >>>>> get rid of it. And the cost of that rash action to get rid of it? >>>>> Basically nothing. Hence my advice: Dither and don’t worry about it—or >>>>> listen to the residual up close and see if there’s nothing to worry >>>>> about, if you prefer. >>>>> >>>>> >>>>>> On Feb 3, 2015, at 10:24 PM, Didier Dambrin <di...@skynet.be> wrote: >>>>>> >>>>>> Sorry, but if I sum up this video, it goes like this: >>>>>> you need dithering to 16bit and I'm going to prove it, then the video >>>>>> actually proves that you don't need it starting at 14bit, but adds "it's >>>>>> only because of the nature of the sound I used for demo". >>>>>> >>>>>> ..then why not use a piece of audio that does prove the point, instead? >>>>>> I know why, it's because you can't, and dithering to 16bit will never >>>>>> make any audible difference. >>>>>> It's ok to tell the world to dither to 16bit, because it's nothing >>>>>> harmful either (it only mislays people from the actual problems that >>>>>> matter in mixing). But if there is such a piece of audio that makes >>>>>> dithering to 16bit any audible, without an abnormally massive boost to >>>>>> hear it, I'd like to hear it. >>>>>> >>>>>> Andrew says he agrees, but then adds that it's important when you >>>>>> post-edit the sound. Yes it is, totally, but if you're gonna post-edit >>>>>> the sound, you will rather keep it 32 or 24bit anyway - the argument >>>>>> about dithering to 16bit is for the final mix. >>>>>> >>>>>> To me, until proven otherwise, for normal-to-(not abnormally)-high >>>>>> dynamic ranges, we can't perceive quantization above 14bit for audio, >>>>>> and 10bits for images on a screen (debatable here because monitors >>>>>> aren't linear but that's another story). Yet people seem to care less >>>>>> about images, and there's gradient banding all over the place. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -----Message d'origine----- From: Andrew Simper >>>>>> Sent: Wednesday, February 04, 2015 6:06 AM >>>>>> To: A discussion list for music-related DSP >>>>>> Subject: Re: [music-dsp] Dither video and articles >>>>>> >>>>>> Hi Nigel, >>>>>> >>>>>> Isn't the rule of thumb in IT estimates something like: "Double the >>>>>> time you estimated, then move it up to the next time unit"? So 2 weeks >>>>>> actually means 4 months, but since we're in Music IT I think we should >>>>>> be allowed 5 times instead of 2, so from my point of view you've >>>>>> actually delivered on time ;) >>>>>> >>>>>> Thanks very much for doing the video! I agree with your recommended >>>>>> workflows of 16 bit = always dither, and 24 bit = don't dither. I >>>>>> would probably go further and say just use triangular dither, since at >>>>>> some time in the future you may want to pitch the sound down (ie for a >>>>>> sample library of drums with a tom you want to tune downwards, or >>>>>> remixing a song) then any noise shaped dither will cause an issue >>>>>> since the noise will become audible. >>>>>> >>>>>> All the best, >>>>>> >>>>>> Andrew >>>>>> >>>>>> -- cytomic -- sound music software -- >>>>> -- >>>>> dupswapdrop -- the music-dsp mailing list and website: >>>>> subscription info, FAQ, source code archive, list archive, book reviews, >>>>> dsp links >>>>> http://music.columbia.edu/cmc/music-dsp >>>>> http://music.columbia.edu/mailman/listinfo/music-dsp >>>> >>>> -- >>>> dupswapdrop -- the music-dsp mailing list and website: >>>> subscription info, FAQ, source code archive, list archive, book reviews, >>>> dsp links >>>> http://music.columbia.edu/cmc/music-dsp >>>> http://music.columbia.edu/mailman/listinfo/music-dsp >>>> >>>> ----- >>>> Aucun virus trouvé dans ce message. >>>> Analyse effectuée par AVG - www.avg.fr >>>> Version: 2015.0.5645 / Base de données virale: 4281/9056 - Date: 04/02/2015 >>>> -- >>>> dupswapdrop -- the music-dsp mailing list and website: >>>> subscription info, FAQ, source code archive, list archive, book reviews, >>>> dsp links >>>> http://music.columbia.edu/cmc/music-dsp >>>> http://music.columbia.edu/mailman/listinfo/music-dsp >>> >>> -- >>> dupswapdrop -- the music-dsp mailing list and website: >>> subscription info, FAQ, source code archive, list archive, book reviews, >>> dsp links >>> http://music.columbia.edu/cmc/music-dsp >>> http://music.columbia.edu/mailman/listinfo/music-dsp >> >> -- >> dupswapdrop -- the music-dsp mailing list and website: >> subscription info, FAQ, source code archive, list archive, book reviews, dsp >> links >> http://music.columbia.edu/cmc/music-dsp >> http://music.columbia.edu/mailman/listinfo/music-dsp > -- > dupswapdrop -- the music-dsp mailing list and website: > subscription info, FAQ, source code archive, list archive, book reviews, dsp > links > http://music.columbia.edu/cmc/music-dsp > http://music.columbia.edu/mailman/listinfo/music-dsp -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
