* Brandon Hale <bthaleproductions@xxxxxxxxx> [2021-03-01 16:53]: > Thanks for all of this good info Peter. I didn't know about the sursound > mailing list, and will experiment with that pd library you told me about. > This is all a learning experience for me. > > When you say 5th order 3d, wouldn't that only be 36 loudspeakers? The basic relation you have to consider is this classic one: In order to reproduce a 2D soundfield (planar, loudspeaker ring) of order N you need at least L loundspeakers (N+1)^2 =< L so for 5th order it would be 6^2 = 36 as you mention, but thanks to the greater-equal sign you can always use more speakers. You will not exploit a possibly higher order, but as Fons remarked, there might not be much spatial resolution to gain. Give it a try, perhaps subscribe to the pd list for more help with the objects if needed, and take a listen. cheers, P > > Brandon Hale > > On 3/1/21 10:12 AM, Peter P. wrote: > > Hi, > > > > * Brandon Hale <bthaleproductions@xxxxxxxxx> [2021-03-01 15:37]: > > > > 1. Computing decoders for arbitrary speaker positions is still some > > > > sort of 'black art' unless the postions form a more or less regular > > > > grid. Don't believe everything about automated methods claiming to > > > > do this. > > > This is good to keep in mind. Have you ever seen the ICST plugins for max > > > msp? Those objects have a method of putting in xyz coordinates for its > > > ambisonic decoders. > > I think Fons means that building "good" decoders is some sort of a black > > art for a given (non-regular) layout. All technical solutions allow xyz > > coordinate entry and come up with a static decoder matrix (this is > > really just a matrix of static floating point numbers, you could write > > this on a beer mat if pubs were open). > > > > > Where I work at, we use this to output ambisonics to all > > > of our spaces at ICAT, including the Cube > > > <https://icat.vt.edu/studios/the-cube.html>. It does work well, but I do > > > know of colleagues who complain about how "fuzzy" the spatialization is. Do > > > these kinds of decoders fudge the decoding to achieve output? I really want > > > to find something like this for Linux. > > If you want to get the full craze of kinds of decoder discussions you > > might want to sign up to the sursound mailing list. > > > > > > 3. I really can't imagine anything done with speakers that would > > > > require 7th order. Even with 4th or 5th order, if you have enough > > > > speakers to use that, the angles between the speakers are so small > > > > that even phantom images in between speakers are for all practical > > > > purposes perfect. > > > The reason I ask is because I want to find a Linux-based system for the > > > Cube, which has 138 speakers arranged in a rectangular prism. I am > > > constantly looking for a way to decode ambisonics to it without having to > > > use max msp. > > Use the Pd objects I mentioned and go for 5th order 3D which will create > > output signals for all 138 speakers. Also correct the > > speaker distances with short delays and compensate for level differences > > by ear or by using a SPL meter. > > > > > I have not had much luck finding something standalone or in pd. > > > Maybe I should learn supercollider? It can be hard to find decoders that go > > > to 10th or 11th order. > > Again, its not a question of max vs pd vs sc3 vs csound, but of the > > usefulness of doing it. If you already have these 138 speakers mounted, > > then configure one of the mentioned solutions to use the corresponding > > order and have a listen. > > > > > > 4. To do anything similar to WFS 'internal sources' (i.e. in front > > > > of the speakers) in any practical frequency range, you'd need the > > > > same amount of speakers as WFS would, and of course the required > > > > very high order input. > > > At work, I may be getting hold of 64 AVB speakers that I can arrange in a > > > line to experiment with WFS. The great thing about this is the speakers are > > > AVB, and not Dante. I may be able to play with these speakers on Linux. Of > > > course, there is at least one WFS processor (is that the right term?) that I > > > know of in max. But, I find max too annoying and locked down for real use, > > > and of course I want to do it on Linux! > > I managed to get ssr~ to run as a pd external a few years ago. > > Furthermore be aware that the distance between the speakers determines > > the upper frequency limit. I don't know if AVB introduces some latency > > between speakers. Fons might know something about this perhaps? > > _______________________________________________ > > Linux-audio-user mailing list > > Linux-audio-user@xxxxxxxxxxxxxxxxxxxx > > https://lists.linuxaudio.org/listinfo/linux-audio-user > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user@xxxxxxxxxxxxxxxxxxxx > https://lists.linuxaudio.org/listinfo/linux-audio-user _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx https://lists.linuxaudio.org/listinfo/linux-audio-user
