Re: [Sursound] Ambisonic UHJ Stereo decoder to speaker feeds
On Wed, Mar 02, 2022 at 04:18:26AM +0200, Sampo Syreeni wrote: > ...unless you're trying something new, like fully general time variant HOA > reverberation. We were talking about rendering historical UHJ recordings. > ... which already at m=3 leaves you with 16 independent input and output > signals, and as such 16^2==256 cross-connections, convolutions, between the > components. This is no longer a trivial load for any current processor, > or even a processor array. I'm routinely such convolution matrices on a 10 year old PC. No problem at all. > The game's designer would typically have to model those spaces as separate, > and somehow interpolate between the solutions, Again, we were talking about rendering UHJ. Not games. But even for games, you don't need exact solutions. Just something that works. This is true for any type of content creation. > If you read my comments, I *never* do that. FFS, I'm a libertarian, much of > the Thatcher/Reagan sort: "There are no free lunches." I will refrain to comment on that. > Yes, but if by unisono you actually mean "fully in phase" I don't as you should know. Otherwise tell me how to make two or more people sing 'in phase'. f> > In practice such things become possible in practice if you start with > > something like third or higher order. But the maths are by no means > > trivial. > > I'd in fact call the math pretty much trivial. It's mostly just about LTI > filtering, convolution. Its *optimized* form might not be quite as nice, but > the basic framework is just same-ol'. It isn't. You clearly have no idea of what is involved. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] Ambisonic UHJ Stereo decoder to speaker feeds
On 2022-02-28, Fons Adriaensen wrote: General purpose libraries doing efficient zero delay convolution using multiple partition sizes (as suggested by Gardner) do exists. But they are complete overkill for the simple problem at hand (decoding UHJ). In a sense they are overkill, but in another they are not. Because *if* you can do an easy API to a zero-delay convolution library, which also admits full parallelization, and as the Gardner framework has it also exhibits constant and asymptotically optimal computational load, the thing is a no-worries plugin everybody can and will use. If you *don't* have guarantees like that, developers won't adopt it for fear of complexity, varying load which freezes your customer's phone up, because the extra latency just doesn't work too well if a library is embedded in a wider feedback loop (binaural following comes to mind, in gaming), or just sheer average load. Even the most basic FFT-based implentation wouldn't take more than one percent CPU time on a ten year old PC or something like a Raspberry Pi. Indeed, and if you run such algorithms on a DSP, with say modulo addressing and a proper streaming memory access pipeline, the hit can be even less... ...unless you're trying something new, like fully general time variant HOA reverberation. The computational load, especially if you have to do a plug-in zero delay library, quickly multiplies. For instance, if you do full periphonic third order reverberation, you have n=(m+1)^2 signals to contend with, which already at m=3 leaves you with 16 independent input and output signals, and as such 16^2==256 cross-connections, convolutions, between the components. This is no longer a trivial load for any current processor, or even a processor array. Not least because of the memory bandwidth and cache contention concerns. Of course sane engineering would call for the dimensionality problem to be reduced. Say, do a multidimensional KLT transform or at least a DCT before you process your signal set, and then cut off the extra dimensions which cease to significantly contribute to the final processing. As you know, they can be proven to fall off fast rather generally, in this setup, with most musically relevant steady state conditions. Except they can *not* be proven to do so when the system function is derived from geometrical-acoustical, time-variant reasons, such as is the case in first-person-shooter games. Think about when you as the shooter come from a narrow passage way into a broad arena. The game's designer would typically have to model those spaces as separate, and somehow interpolate between the solutions, because a global solution to the acoustic field equation is *very* much beyond the capability of *any* hardware out there. But then if you're doing third order ambisonic, even the transitory rendered field is rather hard to calculate. It's *especially* hard to calculate if you don't have a zero-delay, no-nonsense, constant load-and-latency library at your disposal, which does *not* require any extra calls to some weird principal component machinery in order to work. (And you know, over multidimensional signal sets, that machinery has *never* been put into a constant or even limited effort framework, like Gardner did for zero delay convolution; your game now freezes up because the audio guy decided to optimize something in the long run, at you lose the tournament.) Some people think they can build a perpetuum mobile. Or extract information out of nothing. If you read my comments, I *never* do that. FFS, I'm a libertarian, much of the Thatcher/Reagan sort: "There are no free lunches." For each finite-order B-format, there are wildly different source distributions that will produce exactly the same B-format signals. Indeed. But the vast majority of them are physically implausible. For instance, it is implausible that there would be more than tens of thousands of point sources or more than a ten extended sources within any any acoustical image captured by an ambisonic mic, or indeed synthetically rendered into any feed. Certainly they won̈́'t be active at the same time and with the precise same frequency distribution. Which means that we can legitimately assume something about our signal set which otherwise needn't be true. We can make a priori assumptions, and then go from them to decoding solutions which otherwise would not be legitimate. We can do what in other contexts is called "superresolution". It's not "something from nothing", but rather "something for something". And we've been doing this the whole time ambisonic existed. Because the classical first order decoding solution which lead us to them shelf filters is already a superresolution one: it assumes a single directional source, and two different metrics, from Makita theory. Higher up the power criterion, lower down the linear interference theory. But all of that in the
Re: [Sursound] Tiltification Celebration
Or any builder. Have you ever seen a carpenter, bricklayer or any of those sort of trades use their phone? I certainly haven't, and you won't because they are crap... If you do, i would recommend you get someone else... I tried to work out the angle and position of some speakers once, never again... Steve On Tue, 1 Mar 2022, 21:09 Fons Adriaensen, wrote: > On Tue, Mar 01, 2022 at 08:21:19PM +0100, Tim Ziemer wrote: > > > The weakness of the system is not the precision of the bubble location, > > which is almost perfect, but the human’s uncertainty due to bubble > > curvature, refraction, etc. > > Only if you don't know how to read it. > > Such bubble levels are used to set up optical instruments > (transits, theodolites, total stations,...) which require > very high levelling accuracy. Typically less than one > minute of arc. Ask any surveyor if you don't believe me. > > Ciao, > > -- > FA > > > > > ___ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > edit account or options, view archives and so on. > -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20220301/5e727423/attachment.htm> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] Tiltification Celebration
On Tue, Mar 01, 2022 at 08:21:19PM +0100, Tim Ziemer wrote: > The weakness of the system is not the precision of the bubble location, > which is almost perfect, but the human’s uncertainty due to bubble > curvature, refraction, etc. Only if you don't know how to read it. Such bubble levels are used to set up optical instruments (transits, theodolites, total stations,...) which require very high levelling accuracy. Typically less than one minute of arc. Ask any surveyor if you don't believe me. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] Tiltification Celebration
Hi Fons, The weakness of the system is not the precision of the bubble location, which is almost perfect, but the human’s uncertainty due to bubble curvature, refraction, etc. I think the graphic perfectly demonstrates that: https://pixabay.com/photos/spirit-level-tool-craft-to-build-2081193/ Best, Tim ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ Dr. Tim Ziemer Bremen Spatial Cognition Center University of Bremen 28359 Bremen Office: Cartesium 3.13 Enrique-Schmidt-Str. 5 Fon + 49 (0) 421-218-64280 Fax + 49 (0) 421-218-64239 zie...@uni-bremen.de https://bscc.spatial-cognition.de/ziemer > On 1. Mar 2022, at 14:11, Fons Adriaensen wrote: > > On Tue, Mar 01, 2022 at 01:11:52PM +0100, Tim Ziemer wrote: > >> Errors of more than one degree are very common. > > Where do you get that ? Just look up some specs. Even a cheap > (20 Euro) plastic bubble level can have a sensitivity [1] of > 1/2000 (0.03 degrees). > > Absolute accuracy is easy to check, just turn the level by > 180 degrees. > > Those used by e.g. surveyors (still analog 'bubble') can be > orders of magnitude better. > > Most people have absolutely no idea of how accurate old-school > analog things can be. Manufacturing and use of some of those > is based on hundreds of years of experience. > > [1] Sensitivity is the inclination required to move the bubble > by one graduation line. Graduation lines are typically 2 mm > apart. > > Ciao, > > -- > FA > > ___ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit > account or options, view archives and so on. -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20220301/f9632064/attachment.htm> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] Tiltification Celebration
On Tue, Mar 01, 2022 at 01:11:52PM +0100, Tim Ziemer wrote: > Errors of more than one degree are very common. Where do you get that ? Just look up some specs. Even a cheap (20 Euro) plastic bubble level can have a sensitivity [1] of 1/2000 (0.03 degrees). Absolute accuracy is easy to check, just turn the level by 180 degrees. Those used by e.g. surveyors (still analog 'bubble') can be orders of magnitude better. Most people have absolutely no idea of how accurate old-school analog things can be. Manufacturing and use of some of those is based on hundreds of years of experience. [1] Sensitivity is the inclination required to move the bubble by one graduation line. Graduation lines are typically 2 mm apart. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] Tiltification Celebration
Hi Fons, Thanks for your feedback! I would argue: A digital spirit level can be way more precise than smartphone sensors for sure. But a physical spirit level with the curved air bubble inside a colored liquid that has to be placed centrally between two lines drawn on the liquid filled tube https://pixabay.com/photos/building-tiler-ceramic-tiles-1080597/ is way less precise than a fraction of a degree. Think of it: You have reflections, and refractions, and the bubble curvature: https://pixabay.com/photos/spirit-level-tool-craft-to-build-2081193/ Errors of more than one degree are very common. Still, you are right: We definitely show off! Cheers, Tim ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ Dr. Tim Ziemer Bremen Spatial Cognition Center University of Bremen 28359 Bremen Office: Cartesium 3.13 Enrique-Schmidt-Str. 5 Fon + 49 (0) 421-218-64280 Fax + 49 (0) 421-218-64239 zie...@uni-bremen.de https://bscc.spatial-cognition.de/ziemer > On 1. Mar 2022, at 11:39, Fons Adriaensen wrote: > > On Tue, Mar 01, 2022 at 09:57:31AM +0100, Tim Ziemer wrote: > >> Through this app many people have learned >> - what sonification is >> - that they are well capable of leveling without looking >> and, hopefully, started imagining what else sonification can offer to their >> lives. > > Nice idea, but this (from the app store) is really over the top: > > The auditory feedback is more precise than a physical spirit > level with an air bubble in liquid. > > Normal spirit levels (not even talking about those used by > surveyors or engineers) are accurate and stable to a small > fraction of a degree, one minute is absolutely not exceptional. > > There is no way that the cheap sensors in a smartphone can > even come close to this. > > Ciao, > > -- > FA > > > > ___ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit > account or options, view archives and so on. -- next part ------ An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20220301/2d848964/attachment.htm> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
Re: [Sursound] Tiltification Celebration
On Tue, Mar 01, 2022 at 09:57:31AM +0100, Tim Ziemer wrote: > Through this app many people have learned > - what sonification is > - that they are well capable of leveling without looking > and, hopefully, started imagining what else sonification can offer to their > lives. Nice idea, but this (from the app store) is really over the top: The auditory feedback is more precise than a physical spirit level with an air bubble in liquid. Normal spirit levels (not even talking about those used by surveyors or engineers) are accurate and stable to a small fraction of a degree, one minute is absolutely not exceptional. There is no way that the cheap sensors in a smartphone can even come close to this. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
[Sursound] Tiltification Celebration
***With apologies for cross-posting*** Dear Audio Artists and Researchers, Today we celebrate 20,000 downloads of Tiltification, our sonification-based spirit level app for android: https://play.google.com/store/apps/details?id=de.uni_bremen.informatik.sonification_apps and iOS: https://apps.apple.com/de/app/tiltification/id1557133147 Big thanks to those of you who downloaded, reviewed and rated our app, and supported us through word-of-mouth. Through this app many people have learned - what sonification is - that they are well capable of leveling without looking and, hopefully, started imagining what else sonification can offer to their lives. Those of you who haven't tested it yet: We are thankful for every download, rating and feedback! Those of you who see room for improvements: Feel free to implement and release your own version using our open source repository: https://sonification.uni-bremen.de/open-source.html Thank you for your support! Tim and the students from the "Sonification Apps" master's project https://sonification.uni-bremen.de/ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ ♪ ♫ Dr. Tim Ziemer Bremen Spatial Cognition Center University of Bremen 28359 Bremen Office: Cartesium 3.13 Enrique-Schmidt-Str. 5 Fon + 49 (0) 421-218-64280 Fax + 49 (0) 421-218-64239 zie...@uni-bremen.de https://bscc.spatial-cognition.de/ziemer -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20220301/8b906126/attachment.htm> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
