[LAU] question about FOSS WFS implentations

[Ivica Ico Bukvic]

> -----Original Message-----
> From: Fons Adriaensen [mailto:fons at linuxaudio.org]
> Sent: Tuesday, December 17, 2013 11:04 AM
> To: Ivica Bukvic
> Cc: A list for linux audio users
> Subject: Re: [LAU] question about FOSS WFS implentations
> 
> On Tue, Dec 17, 2013 at 10:14:45AM -0500, Ivica 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.
> 
> 'Filling the gaps' with virtual speakers doesn't change things - for the
> same reason that you can't pull yourself up by your bootstraps.
> 
> Consider the simple case of a plane wave from a direction orthogonal
> to the line of speakers. All speakers will get the same signal. To
> create a virtual speaker between every two adjacent real ones, those
> two would just have to get more of the same signal. So nothing changes,
> except at the ends of the line (and you may rediscover tapering).

What if the denser line is positioned a distance behind the original
speakers (as in the entire space is actually bigger with a denser array
encircling the real physical array)? Sure, this would do nothing for an
orthogonal direction, but it may improve the perception of other angles, no?

> 
> Ambisonic reproduction will create images 'projected on the line of
> speakers' a virtual source in between the speakers will appear at
> the same distance as the real speakers. It's possible to change this
> using near-field compensation, but only for low frequencies.
> 
> Distance illusions can be created by exploiting psycho-acoustic
> effects rather than physics. I suspect systems such as S.E. are
> particularly good at this.
> 
> 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)