[PD] 8 channel circle panner, how?

[Dudley Brooks]

A quick question, of purely academic interest:

In theory, wouldn't it be possible to get 3D spatialization with just 
four speakers arranged in, say, the corners of a tetrahedron, such as 
one directly above and three in an equilateral triangle below the 
listener's "horizon" (i.e. the plane of the listener's ears)?  I'm sure 
that eight speakers would be preferable -- maybe fewer "dead spots"?  
But, strictly speaking, four could do it, right?

On 9/10/19 12:39 PM, Roman Haefeli wrote:

> On Tue, 2019-09-10 at 14:43 -0300, Alexandre Torres Porres wrote:
>>
>> Em ter, 10 de set de 2019 às 06:15, Roman Haefeli <reduzent at gmail.com
>>> escreveu:
>>> For true spatialization
>> what is "true spatialization"?
> I mean true spatialization as opposed to simple panning. You asked for
> a panner and you were given a panner. Then you said you were thinking
> of a more sophisticated panner. And I said what you want might be
> spatialization that not only emulates a sound source traveling along a
> virtual circle, but that is able to emulate also every position in
> between. Sounds to me like true spatialization. But I'm only guessing.
> I can't read your mind, don't know what you really want. I can only
> read you mails. Only apt has super-cow powers.
>
>
>> And why would else/pan4~ not be "truthful"?
> Did I say it is not "truthful"? I'm sure it's a very true panner. It's
> even 2D (it positions the sound source anywhere between the speakers,
> not only on the outlines). Now, isn't that exactly what you want, but
> only with four channels? I'm confused now.
>
>>> - it sounds to me that is what you're aiming at
>>> - use Ambisonics[1].
>> hmm, I don't really know, and here's a silly question. It seems to me
>> ambisonics tries to locate a sound source in a 3D sphere, but the
>> idea would actually be to pan the sound source in a 2D circle space.
> It's a totally fine question. I'm not an expert either. Ambisonics is
> able to render in 3D, but you can also do 2D (for instance, if you
> place all speakers on the same plane). What I understand is special
> about Ambisonics, is that you do not need to know beforehand for which
> speaker setup you're making a recording or a rendering for. Only the
> decoder needs to know the exact configuration of the speakers. This
> allows for setups that are not a perfect circle or sphere.
>
>
>> So, can ambisonics help there or is it overcomplicated for that
>> matter? And how is it possible with 8 speakers to simulate a 3D
>> sphere?
> Again, not an expert speaking here, but depending on your goals you
> need that complexity. If your speaker setup is for some reason not a
> perfect circle, or the positions are not evenly spaced, the image of
> your virtual sound source(s) is distorted. If  you want to account for
> that, it's probably easier to use Ambisonics than figuring out all the
> calculations on your own. Do you care for a good reproduction of
> spatial image? Do you need the flexibility that Ambisoncis gives you?
> Do you want re-invent things each time the setup is different? Would
> like to be able to switch between 2D and 3D with the same system? Do
> you want your piece to be played "correctly" at some other venue that
> is not the studio where you worked on your piece?
>   
> I'm not saying you want all that. I'm just thinking that the more you
> deal with the stuff, the more those aspect are going to matter.
>
>>> There seem to be Pd externals for this.
>> yeah, I know, just not sure if all the complicated encoding and
>> everything is indispensable and stuff
> I don't know. I'm not sure if what you want is different from
> [else/pan4~], but with 8 channels...
>
> Roman
>
>
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