17 Dec
2013
17 Dec
'13
4:14 p.m.
On Dec 17, 2013 5:29 AM, "Fons Adriaensen" <fons(a)linuxaudio.org> wrote:
On Mon, Dec 16, 2013 at 11:13:18PM -0500, Ivica Ico Bukvic wrote:
I had an opportunity to listen to their system and even though it was quite
sparse it still delivered a very compelling image even close to the
speakers. If the system was using anything in the way of ambisonics it
would have done so only using the actual horizontal array. Given that
highest repreducible frequency is directly related to the distance between
the speakers I am wondering if this may be because they are also trying to
render waves from virtual speakers as they propagate through the real
speakers as well as using a selection of speakers to render certain sounds
as per recent publications in this area.
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
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)
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