On Fri, Jan 07, 2011 at 01:21:37PM +0100, Giso Grimm wrote: For setting up a _convinving_ demo system the best advice I can give ATM is: * Use ambdec with one of the regular layouts for which a configuration is provided. * Use a set of identical speakers, of reasonable quality. * Carefully check and adjust levels. If you really want to fully understand things there is no way besides diving into the maths. This is in particular the case for higher order. The PhD theses of Daniel and Moreau are good starting places in that case, and understanding what is explained there is more or less a requirement before you can go on reading e.g. some of the proceedings of the AMB symposia, the work of other researchers, etc. What does not exist AFAIK are publications that translate the maths into more intuitive language. For the good reason that it is *quite difficult* to do that without going astray, much more difficult than for e.g. general DSP theory. I've tried to do it many times in posts on this list and others, and in private communication. Once people start asking the right questions it can be very hard to avoid the maths, or to present them in more consumable format. For me, any intuitive, 'common language' understanding I may have is not the result of just knowing the theory but of working with it - using it to calculate or simulate things and trying to understand the results in practical terms. That takes time, but I don't think there is any alternative for it. Compare it to your knowledge of ancient instruments and of the interpretation and performance issues of the music composed for them - it's not something you can acquire in a few weeks. And it can't be explained without referring to lots of other knowledge including in this case music theory and history. This more or less follows directly from the theory. This is *black art* at the moment. There are no general purpose algorithms to do it. That does not mean you can't find a decoder for a given layout, but it will be a compromise far below what it *could* be. The methods I use are a combination of semi-automatic procedures and manual tweaking with feedback from simulations. The latter becomes quite hard as order goes up, I wouldn't even try anything above 3rd order that way. There is some work being done to develop automated systems, e.g by Bruce Wiggins (univ. of Derby) and Franz Zotter (IEM, Graz), but it remains quite experimental at the moment. One thing that is clear to me is that irregular layouts can be optimised only if you have higher order input. The information to do it just isn't present in e.g. first order recordings. For example, you can reproduce first order on a 5.0 layout, and it works, but result are *much* better for second order. And 5.0 is more or less the simplest case to consider. The best reference here IMHO are the publication of Joern Nettingsmeier who has probably more experience with real life (in particular large) systems than any practising sound engineer I know. I expect he will present some more at the next LAC. Ciao, -- FA There are three of them, and Alleline.

On Fri, Jan 7, 2011 at 4:16 PM, Niels Mayer <nielsmayer(a)gmail.com> wrote: i quote: "Certainly, listening to music or even watch high definition movies will feel more booming with Nokia X7-00." ambisonics assumes a speaker in the midst of an array of speakers that point more or less in the general direction of the listener's head. this phone is just a gimmick. the nokia phone has so little to do with any kind of "spatial sound" that i hardly know where to begin.

On Fri, Jan 7, 2011 at 2:00 PM, Leonardo Palomares <leoave(a)gmail.com> wrote: on second though, maybe for this special model (bunch of front "surround" speakers) the brand has to be changed to "Mythsubishi". Any way, wife and children are full happy with it. :D Leo

On 01/07/2011 11:35 PM, Niels Mayer wrote: if you're interested in beamforming with spherical speakers, check out franz zotter's and andy schmeder's papers. executive summary: it can be done, but it requires quite some oomph if you want to cover more than just one or two octaves. implementing this on a cell phone will always remain a marketing gimmick without any real value. no, it's not. that's andy schmeder's project i was talking about. it does work, but it's not really about surround sound (unless you happen to know your room exactly, in which case you can bouce beams off of walls and get some sort of surround effect, but with huge artefacts and sidelobes). these speakers are for acoustic measurements and simulation of radiation patterns. you could for instance sample a violin with a sphere of microphones, and use one of these spherical speakers to create something that looks like a violin and quacks like a violin. you can shoehorn ambisonics theory into this "inside out" application. dylan menzies (and maybe dave malham, too) has formulated this idea some years ago and called it "o-format". but it's not generally useful. you can do circular beamforming, but it will be even less effective than spherical. think huge amounts of destructive interference and ugly, ugly side lobes. for beamformed bass, you need ridiculously long coil travel and loooots of power.