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<pre class="moz-quote-pre" wrap="">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.</pre>
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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
<a moz-do-not-send="true"
href="https://icat.vt.edu/studios/the-cube.html">the Cube</a>.
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.<br>
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<pre class="moz-quote-pre" wrap="">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.</pre>
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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.</p>
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<pre class="moz-quote-pre" wrap="">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.</pre>
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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!</p>
<p>Thanks for the detailed points,</p>
<p>Brandon Hale<br>
</p>
<div class="moz-cite-prefix">On 2/26/21 12:17 PM, Fons Adriaensen
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:20210226171702.aqmn3knfknahzj2n@mail1.linuxaudio.cyso.net">
<pre class="moz-quote-pre" wrap="">On Fri, Feb 26, 2021 at 11:58:28AM -0500, Brandon Hale wrote:
</pre>
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<pre class="moz-quote-pre" wrap="">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.
</pre>
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<pre class="moz-quote-pre" wrap="">
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,
</pre>
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