[LAU] ssr and alternatives

Fons Adriaensen fons at linuxaudio.org
Fri Feb 26 18:17:02 CET 2021

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.



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