Re: [LAU] ssr and alternatives

> 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. 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.

> 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. 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.

> 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!

Thanks for the detailed points,

Brandon Hale

On 2/26/21 12:17 PM, Fons Adriaensen wrote:
> On Fri, Feb 26, 2021 at 11:58:28AM -0500, Brandon Hale wrote:
>
>> Ambdec looks nice, but I wish there wasn't a limit on order. 36 speakers may
>> not be enough for me. Do you know of anything for beyond 7th order? I wasn't
>> clear enough in my original email, but I am really looking for something
>> that can go past 7th order and can do any speaker placement.
> Ambdec is currently limited at 3rd order, but that could be increased.
> Also it does not compute the actual decoder coefficients, these have
> to be supplied in a preset file.
>
> Keep in mind that
>
> 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.
>
> 2. Higher order means more speakers. 7th order would require at
> least 64, assuming they are in a regular grid, and probably a lot
> more if they are not. Less speakers would mean that the information
> in the higher orders can't be used, and any correctly computed
> decoder will actually just ignore such information.
>
> 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.
>
> 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.
>
>
> Ciao,
>

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Received on Tue Mar 2 04:15:02 2021