32-bit internal floating point is not sufficient for certain DSP tasks and will be plainly audible as causing all sorts of problems, a DF1 at low frequencies is the classic example of this, it causes large amounts of low frequency rumble. This is a completely different thing to the final bit depth of an audio file to listen to.
Andy -- cytomic -- sound music software -- On 7 February 2015 at 02:24, Michael Gogins <michael.gog...@gmail.com> wrote: > > Do not believe anything that is not confirmed to a high degree of > statistical signifance (say, 5 standard deviations) by a double-blind > test using an ABX comparator. > > That said, the AES study did use double-blind testing. I did not read > the article, only the abstract, so cannot say more about the study. > > In my own work, I have verified with a double-blind ABX comparator at > a high degree of statistical significance that I can hear the > differences in certain selected portions of the same Csound piece > rendered with 32 bit floating point samples versus 64 bit floating > point samples. These are sample words used in internal calculations, > not for output soundfiles. What I heard was differences in the sound > of the same filter algorithm. These differences were not at all hard > to hear, but they occurred in only one or two places in the piece. > > I have not myself been able to hear differences in audio output > quality between CD audio and high-resolution audio, but when I get the > time I may try again, now that I have a better idea what to listen > for. > > Regards, > Mike > > > > ----------------------------------------------------- > Michael Gogins > Irreducible Productions > http://michaelgogins.tumblr.com > Michael dot Gogins at gmail dot com > > > On Fri, Feb 6, 2015 at 1:13 PM, Nigel Redmon <earle...@earlevel.com> wrote: > >>Mastering engineers can hear truncation error at the 24th bit but say it is > >>subtle and may require experience or training to pick up. > > > > Quick observations: > > > > 1) The output step size of the lsb is full-scale / 2^24. If full-scale is > > 1V, then step is 0.0000000596046447753906V, or 0.0596 microvolt (millionths > > of a volt). Hearing capabilities aside, the converter must be able to > > resolve this, and it must make it through the thermal (and other) noise of > > their equipment and move a speaker. If you’re not an electrical engineer, > > it may be difficult to grasp the problem that this poses. > > > > 2) I happened on a discussion in an audio forum, where a highly-acclaimed > > mastering engineer and voice on dither mentioned that he could hear the > > dither kick in when he pressed a certain button in the GUI of some beta > > software. The maker of the software had to inform him that he was mistaken > > on the function of the button, and in fact it didn’t affect the audio > > whatsoever. (I’ll leave his name out, because it’s immaterial—the guy is a > > great source of info to people and is clearly excellent at what he does, > > and everyone who works with audio runs into this at some point.) The > > mastering engineer graciously accepted his goof. > > > > 3) Mastering engineers invariably describe the differences in very > > subjective term. While this may be a necessity, it sure makes it difficult > > to pursue any kind of validation. From a mastering engineer to me, > > yesterday: 'To me the truncated version sounds colder, more glassy, with > > less richness in the bass and harmonics, and less "front to back" depth in > > the stereo field.’ > > > > 4) 24-bit audio will almost always have a far greater random noise floor > > than is necessary to dither, so they will be self-dithered. By “almost”, I > > mean that very near 100% of the time. Sure, you can create exceptions, such > > as synthetically generated simple tones, but it’s hard to imagine them > > happening in the course of normal music making. There is nothing magic > > about dither noise—it’s just mimicking the sort of noise that your > > electronics generates thermally. And when mastering engineers say they can > > hear truncation distortion at 24-bit, they don’t say “on this particular > > brief moment, this particular recording”—they seems to say it in general. > > It’s extremely unlikely that non-randomized truncation distortion even > > exists for most material at 24-bit. > > > > My point is simply that I’m not going to accept that mastering engineers > > can hear the 24th bit truncation just because they say they can. > > > > > >> On Feb 6, 2015, at 5:21 AM, Vicki Melchior <vmelch...@earthlink.net> wrote: > >> > >> The following published double blind test contradicts the results of the > >> old Moran/Meyer publication in showing (a) that the differences between CD > >> and higher resolution sources is audible and (b) that failure to dither at > >> the 16th bit is also audible. > >> > >> http://www.aes.org/e-lib/browse.cfm?elib=17497 > >> > >> The Moran/Meyer tests had numerous technical problems that have long been > >> discussed, some are enumerated in the above. > >> > >> As far as dithering at the 24th bit, I can't disagree more with a > >> conclusion that says it's unnecessary in data handling. Mastering > >> engineers can hear truncation error at the 24th bit but say it is subtle > >> and may require experience or training to pick up. What they are hearing > >> is not noise or peaks sitting at the 24th bit but rather the distortion > >> that goes with truncation at 24b, and it is said to have a characteristic > >> coloration effect on sound. I'm aware of an effort to show this with AB/X > >> tests, hopefully it will be published. The problem with failing to dither > >> at 24b is that many such truncation steps would be done routinely in > >> mastering, and thus the truncation distortion products continue to build > >> up. Whether you personally hear it is likely to depend both on how > >> extensive your data flow pathway is and how good your playback equipment > >> is. > >> > >> Vicki Melchior > >> > >> On Feb 5, 2015, at 10:01 PM, Ross Bencina wrote: > >> > >>> On 6/02/2015 1:50 PM, Tom Duffy wrote: > >>>> The AES report is highly controversial. > >>>> > >>>> Plenty of sources dispute the findings. > >>> > >>> Can you name some? > >>> > >>> Ross. > >>> -- > > > > -- > > 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
