[LAU] ssr and alternatives

[Brandon Hale]

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?

Brandon Hale

On 3/1/21 10:12 AM, Peter P. wrote:
> Hi,
>
> * Brandon Hale <bthaleproductions at gmail.com> [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?
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