Re: [Sursound] approximate solutions to the ambisonic decoding problem
On 2012-01-07, Aaron Heller wrote: For others, it is in a special issue on Ambisonics and Spherical Acoustics. Lot's of relevant papers. http://www.ingentaconnect.com/content/dav/aaua/2012/0098/0001 Any ideas on how to get my hands on them? Ingenta has never been within my direct reach, and it seems I'm losing my reach even to ASA/AES/IEEE/AMS, thanks to the nasty downturn in global economics... -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] approximate solutions to the ambisonic decoding problem
On Mon, Jan 09, 2012 at 12:37:01PM +, Dave Malham wrote: Looks like there may be good papers there but they are _fiendishly_ expensive! Even through York's Institutional Access Portal it appears to cost £124.36 (+ 20% VAT) for just _two_ day's access to the issue (I can get a whole _year_ of the entire AES archive for that) and £21.51 (+ VAT) for individual papers. No way I'll be getting those :-( Same here. I wonder how one can justify such prices. And what motivates authors to make their work available in this way. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] approximate solutions to the ambisonic decoding problem
Looks like there may be good papers there but they are _fiendishly_ expensive! Even through York's Institutional Access Portal it appears to cost £124.36 (+ 20% VAT) for just _two_ day's access to the issue (I can get a whole _year_ of the entire AES archive for that) and £21.51 (+ VAT) for individual papers. No way I'll be getting those :-( Dave On 07/01/2012 23:02, Aaron Heller wrote: For others, it is in a special issue on Ambisonics and Spherical Acoustics. Lot's of relevant papers. http://www.ingentaconnect.com/content/dav/aaua/2012/0098/0001 Best... Aaron (hel...@ai.sri.com) Menlo Park, CA US ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- These are my own views and may or may not be shared by my employer /*/ /* Dave Malham http://music.york.ac.uk/staff/research/dave-malham/ */ /* Music Research Centre */ /* Department of Musichttp://music.york.ac.uk/; */ /* The University of York Phone 01904 322448*/ /* Heslington Fax 01904 322450*/ /* York YO10 5DD */ /* UK 'Ambisonics - Component Imaging for Audio' */ /*http://www.york.ac.uk/inst/mustech/3d_audio/; */ /*/ ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] approximate solutions to the ambisonic decoding problem
On Sat, Jan 7, 2012 at 1:48 AM, Franz Zotter zot...@iem.at wrote: Hi, On Friday 30 December 2011 03:37:42 Aaron Heller wrote: Are these available? The conference site still shows To be determined. http://www.vis.uky.edu/ambisonics2011/proceedings.php I asked the authors for their papers to provide a replacement solution on our webspace: http://ambisonics-symposium.org/proceedings-of-the-ambisonics-symposium-2011 Thanks Franz. I've been reading though your Acta Acustica paper. Nice work, well written. I'll have some questions at some point, as I have access to two arrays that would benefit from the techniques you outline. For others, it is in a special issue on Ambisonics and Spherical Acoustics. Lot's of relevant papers. http://www.ingentaconnect.com/content/dav/aaua/2012/0098/0001 Best... Aaron (hel...@ai.sri.com) Menlo Park, CA US ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] approximate solutions to the ambisonic decoding problem
Seems not... I already got some of the papers from personal websites and via e-mail; I will try to gather this year's papers and put them on our webspace. Franz Zotter http://iaem.at/Members/zotter Institut für Elektronische Musik und Akustik Kunstuniversität Graz Am 30.12.2011 um 03:37 schrieb Aaron Heller hel...@ai.sri.com: On Thu, Dec 29, 2011 at 3:06 PM, Franz Zotter zot...@iem.at wrote: ... see papers of last Ambisonics Symposia ... Are these available? The conference site still shows To be determined. http://www.vis.uky.edu/ambisonics2011/proceedings.php Aaron Heller (hel...@ai.sri.com) Menlo Park, CA US ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] approximate solutions to the ambisonic decoding problem
Hi, Am 24.12.2011 um 07:38 schrieb Sampo Syreeni de...@iki.fi: I wouldn't dare to claim I have a solution to this overall problem, of course. But one part of it interests me above most, and seems to me to be a stepping stone to more general solutions as well: the problem with ill-conditioned decoder matrices. They after all come from too irregularly spaced speakers, either in space, or with regard to the highest order spherical harmonical function being decoded. A big part of the problem is even obvious in a continuous representation: if we were able to synthesize spherical harmonics on a dense (nearly continuous) surrounding loudspeaker setup with gaps that were left uncovered by loudspeakers, we could try to do so by driving the setup with the spherical harmonic patterns. However, the analysis of this continuous pattern with holes would differ from the original. If we try to pre-condition the synthesized pattern so that the analysis matches the original wish, this pre-conditioning is also ill-conditioned when the gaps are big. Abstractly, this explains the biggest reason for ill-conditioning on 3D arrangements. One solution is to build Slepian functions from the spherical harmonics for the domain between the gaps, as suitable analysis-synthesis pair (see papers of last Ambisonics Symposia). However, everything stays in the L2 norm sense. In there I somehow feel one of the numerical L^1 optimization methods such as basis pursuit could perhaps be brough to bare, in a dual formulation. Especially because of the connection with the usual L^2 norm, so essential to the HF optimization problem, via regularization. Has anybody ever worked with something like this? I mean, even if it's numerical and not closed-form, this sort of stuff at least has solid convergence proofs behind it and all. And at least my hind-brain tells me it could lead to a solid, systematic means of controlling undue gain in even highly irregular rigs. You will find papers from Nicolas Epain and his colleagues using the keyword compressive sensing or sampling. They did some work that can be seen as a starting point for L1 norm based rendering with sparsity in space. For decoding, I assume that sparsity in the SH domain is more reasonable... someone should try... There will be a paper in the first acta acustica issue in the coming year that improves our work on decoding in Graz. We fixed the L2 norm for Ambisonic decoding there by avoiding mode matching or sampling. This is relevant for outside sweet spot, reverberant field, and HF, and gets rid of the uncontrolled loudness problem of ill-conditioned decoders. It finally yields decoding with constant energy (as it was called usually) for all playback arrangements. This was the biggest drawback of Ambisonics compared to other panning strategies, which can now be solved. Finally, at time there's been some talk of forbidden harmonics in some of the controlled opposites kinda work. Could somebody perhaps tell me how that theory came to be? Because I have a serious feeling it could be systematized and placed into the general framework I seem to be seeing glimpses of, above. Are there?- I would rather say that harmonics become linearly dependent. But you have to employ SVD or eigendecomposition to see which combinations of harmonics are weakly represented in your loudspeaker setup; it often is a complicated complex of combinations. The talk was about forbidden frequencies somewhen, a purely numerical/mathematical problem that can be circumvented and lies mainly in the boundary integral formulations that cannot easily separate interior and exterior problems. It does not occur with other formulations and will never occur with listening environments of realistic electro and room acoustic accuracy. Best regards and a Happy New Year Franz Zotter Institut für Elektronische Musik und Akustik Kunstuniversität Graz ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] approximate solutions to the ambisonic decoding problem
Forget my last paragraphs...misunderstanding. (did not refer to in some of the controlled opposites kinda work). Am 30.12.2011 um 00:06 schrieb Franz Zotter zot...@iem.at: Finally, at time there's been some talk of forbidden harmonics in some of the controlled opposites kinda work. Could somebody perhaps tell me how that theory came to be? Because I have a serious feeling it could be systematized and placed into the general framework I seem to be seeing glimpses of, above. Are there?- [rubbish]. The [rubbish as well]. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] approximate solutions to the ambisonic decoding problem
On Thu, Dec 29, 2011 at 3:06 PM, Franz Zotter zot...@iem.at wrote: ... see papers of last Ambisonics Symposia ... Are these available? The conference site still shows To be determined. http://www.vis.uky.edu/ambisonics2011/proceedings.php Aaron Heller (hel...@ai.sri.com) Menlo Park, CA US ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
[Sursound] approximate solutions to the ambisonic decoding problem
On 2011-12-23, Bo-Erik Sandholm wrote: If you go back in the archives you will find posts where I and Fonz discuss 3 D playback rigs based on having 6 horisontal speakers that can be reused when playing back 3D. As we say in Finnish, asiasta kukkaruukkuun (from the matter (at hand) to pottery or something like that)... Every time someone talks on-list about more than four speakers at a time, I get a definite 3D vibe, evenif 6-8 speakers could just comprise a denser than usual pantophonic rig. Then, such speaker counts most *certainly* do not comprise a dense periphonic one; in fact an arbitrary number of them in that range do not give rise to a periphonic rig which is amenable to most forms of stochastic optimization, against the classical reproduction equations. Unless you place them precisely acccording to the two classical ambisonic solutions (regular or opposite pairs), you're going to be in trouble solving for the decoder coefficients. I wouldn't dare to claim I have a solution to this overall problem, of course. But one part of it interests me above most, and seems to me to be a stepping stone to more general solutions as well: the problem with ill-conditioned decoder matrices. They after all come from too irregularly spaced speakers, either in space, or with regard to the highest order spherical harmonical function being decoded. In there I somehow feel one of the numerical L^1 optimization methods such as basis pursuit could perhaps be brough to bare, in a dual formulation. Especially because of the connection with the usual L^2 norm, so essential to the HF optimization problem, via regularization. Has anybody ever worked with something like this? I mean, even if it's numerical and not closed-form, this sort of stuff at least has solid convergence proofs behind it and all. And at least my hind-brain tells me it could lead to a solid, systematic means of controlling undue gain in even highly irregular rigs. Finally, at time there's been some talk of forbidden harmonics in some of the controlled opposites kinda work. Could somebody perhaps tell me how that theory came to be? Because I have a serious feeling it could be systematized and placed into the general framework I seem to be seeing glimpses of, above. (Good Yule to ya'll, by the way. At the moment I'm looking after some 7-8kg of prime pork, slowly cooking in the oven for our traditional Christmas meal. Also wondering whether my parents will appreciate a full Twilight-saga for one of their presents. :) -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
