Re: [Algorithms] Spherical harmonics for room acoustic modelling
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From: Jon W. <jw...@gm...> - 2010-07-25 20:01:45
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> > I guess the research around the subject somehow died. I remember binaural demonstrations in the early '80s. I also remember being able to buy special heads with a modeled ear and cavities to insert microphones of your choice. Bright orange, in best 70's fashion, if memory serves :-) To find the research that led to those products, I think you have to dig up (gasp!) offline sources, like the Journal of the AES from 30-50 years ago. Obligatory old-man rant: Remember what it was like back when research required spending months traveling to libraries, ordering back issues of journals, and tracking down too-vague references through legwork? I fear those skills are being lost now, because it's easier to believe that something doesn't exist if you can't find it on Google or Citeseer ;-) And I'm not even that old! Sincerely, jw -- Americans might object: there is no way we would sacrifice our living standards for the benefit of people in the rest of the world. Nevertheless, whether we get there willingly or not, we shall soon have lower consumption rates, because our present rates are unsustainable. On Sun, Jul 25, 2010 at 5:12 AM, Samuel Moll <sam...@go...>wrote: > Somehow OT, I think what was missing in the video for the mentioned > siggraph paper (http://gamma.cs.unc.edu/PrecompWaveSim/), was some > sort of model for the human ear. I strongly suspect that for the > virtual recording they just placed two undirected virtual microphones > some 20cm apart, because with headphones it still sounded as though > every sound source was inside your head (Though the sense of space was > great). And I guess that's because in the virtual recording the > virtual external ear is missing, which is mainly responsible for > directional hearing in the real world. Just listen to these videos > (with earphones!) if you have no idea what I'm talking about (these > both model the external ear in some way, I'm not sure if they also > have real room acoustic modelling): > > binaurial demonstration video: > http://www.youtube.com/watch?v=vfViBtIjK4c&feature=related <-- watch > out for the telephone ;) > virtual haircut: > http://www.youtube.com/watch?v=8IXm6SuUigI&feature=related > > Unfortunately there are very little details available publicly, and > those videos have been around for a long time, so I guess the research > around the subject somehow died. > > > BTW, I'm all for better, more sophisticated and computationally > expensive sound in games! Ego-shooters, horror games, how they could > benefit from the equivalent of the telephone above! ;) > > > Samuel > > > On Wed, Jul 21, 2010 at 8:39 PM, Peter-Pike Sloan > <pet...@ho...> wrote: > > Haven't read the whole thread, but here is a paper that will be presented > at > > siggraph this year: > > http://gamma.cs.unc.edu/PrecompWaveSim/ > > You would clearly need to scale back both memory usage and run-time to > make > > this viable for games of course. > > Peter-Pike > > > > ________________________________ > > Date: Tue, 20 Jul 2010 17:13:06 +0100 > > From: ni...@gm... > > To: gda...@li... > > Subject: Re: [Algorithms] Spherical harmonics for room acoustic modelling > > > > Actually I implemented a basic beam tree that used the material > properties > > to estimate reverb in closed environments. The beam tree was too large > for > > detailed outdoor environments, but I suppose if you have a decent mesh > > reduction algorithm you could scale it down, I just never had the time to > > finish this work. > > > > Cheers, > > -Ken Noland > > > > On Sun, Jul 18, 2010 at 11:03 AM, Jon Watte <jw...@gm...> wrote: > > > > I'd have doubts you'd get good enough response time on CPU alone > > > > Actually, the CPU can give you excellent response times if you're using a > > convolution based solution. DJBFFT is a very high performance, > unencumbered > > convolution implementation, and it takes a minimal amount of CPU for a > > single sound stream. The problem comes when you want to combine delay > lines > > to do overlap-add long convolution (or use the variable-window-size > that's > > allegedly still patented by Lake DSP). It starts adding up! The GPU might > be > > good at larger convolutions, but it has higher latency than the CPU. > > I'm not sure Spherical Harmonics is the right solution. Sound reflection > is > > a function of frequency mapping to absorption and directional spread. And > > whereas the eye is only sensitive to three separate frequencies, the ear > is > > sensitive to thousands... And in SH based PRT, you often collapse the > > direction-dependent response into a single term, and filter the three > > frequencies using a separate RGB "diffuse reflectance" texture. If you > > applied the same to sound, you'd probably get a better than nothing, but > you > > might only get good enough that the problems start to become obvious :-) > > (Bass, Mid and Treble, with a fixed reflectance function) > > Sincerely, > > jw > > > > -- > > Americans might object: there is no way we would sacrifice our living > > standards for the benefit of people in the rest of the world. > Nevertheless, > > whether we get there willingly or not, we shall soon have lower > consumption > > rates, because our present rates are unsustainable. > > > > > > > > On Sat, Jul 17, 2010 at 2:23 PM, Oscar Forth > > <os...@tr...> wrote: > > > > OK maybe not spherical harmonic based but gives the same sorta results > and, > > therefore, just as interesting :) > > > > > ------------------------------------------------------------------------------ > > This SF.net email is sponsored by Sprint > > What will you do first with EVO, the first 4G phone? > > Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first > > _______________________________________________ > > GDAlgorithms-list mailing list > > GDA...@li... > > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > > Archives: > > > http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list > > > > > > > ------------------------------------------------------------------------------ > > This SF.net email is sponsored by Sprint > > What will you do first with EVO, the first 4G phone? > > Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first > > _______________________________________________ > > GDAlgorithms-list mailing list > > GDA...@li... > > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > > Archives: > > > http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list > > > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Sprint > What will you do first with EVO, the first 4G phone? > Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > Archives: > http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list > |