[LAU] question about FOSS WFS implentations

[Fons Adriaensen]

On Mon, Dec 16, 2013 at 11:13:18PM -0500, Ivica Ico Bukvic wrote:

> Some preliminary research reveals several FOSS implementations of
> WFS (wave field synthesis). What is not entirely clear is how these
> implementations stack up to something like Sonic Emotion. I presume
> they will be subpar but the question is by how much and in what
> ways?
> 
> Ok, now another question. Is anyone aware of a 3D FOSS WFS
> implementation (multiple horizontal rows) and how hard would it be
> to use?

Given the number of speakers used, the S.E. system can't be pure
WFS except at very low frequencies. It probably uses a combination
of techniques: WFS, some things based on AMB theory, delays, etc.
but they won't tell you more.

But the main difference to open source systems are to be found not
in the rendering system, but in the one used to create and define
the content. In commercial systems this will be very visual, hide
the technicalities, and probably integrate with protools. It will
also be closed and let you do predefined things only. All that 
makes it easier to use for the non-expert.

Open source systems tend to provide less in this area, but will
have interfaces that allow you to define your own production
workflow and tools, usually via OSC. For example, the system
which I developed and installed in Parma will let you control
the position and smooth movements of virtual sources via OSC,
but little more. Anything else has to be build on top of this.
The main tool used here in Parma is a 'mixer' that instead of
really mixing its inputs, controls the rendering engine instead,
while also taking care of changing e.g. reverb levels and delays
in function of source position. For static sources that is 
almost everything you need, apart from standard production
tools. For more dynamic setups I either write ad-hoc code
(usually Python, but you could use SC, Pd, Csound...), or
plugins sending OSC from automation tracks in Ardour.

A WFS system using two or more rows wouldn't be real 3D WFS,
the vertical component would use conventional panning. A real
3D WFS system would require filling the walls with speakers.

Ciao,

-- 
FA

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