[LAD] Attenuation of sounds in 3D space

[Ralf Mardorf]

On Thu, 2010-07-22 at 10:52 -0700, Fernando Lopez-Lezcano wrote:
> On Thu, 2010-07-22 at 14:01 +0200, Ralf Mardorf wrote:
> > On Thu, 2010-07-22 at 01:04 +0200, Arnold Krille wrote:
> > > We are not talking about 5.1 or 7.1 here. These suck big time.
> > > 
> > > We are talking about ambisonics vs. binaurals vs. simple stereo here!
> > 
> > Ok, I noticed this.
> > 
> > Fon's AmbDec is the player for the files from
> > http://www.ambisonia.com/?!
> > 
> > I guess a friend who lives near to my home has at least 8 outputs for an
> > Envy24 sound card and at least a JBL 5.1 setup, so the 5.1 speakers
> > could be used for a minimalist ambisonics.
> 
> Yes. Fons ships an ambdec configuration for playing in a 5.1 setup (it
> is not optimal because the back speakers in a 5.1 setup are too far
> apart but it works - I use it at home). Of course it assumes that the
> 5.1 setup is correct. This link has a diagram of the speaker angles:
> 
>   http://de.wikipedia.org/wiki/5.1
> 
> -- Fernando

The speakers of the 5.1 system should just be used, because they are 5
of the same type and because there are equal amps for the speakers.
There's no need to keep
http://upload.wikimedia.org/wikipedia/de/thumb/4/4e/ITUKreis_Ruhnke.jpg/300px-ITUKreis_Ruhnke.jpg, if the speakers should really be placed correctly for 5.1 at the friends living room at the moment.

If possible I would prefer to replace them in a way that's good for
ambisonics.

        From: Arnold Krille <arnold at arnoldarts.de>
        To: linux-audio-dev at lists.linuxaudio.org
        Subject: Re: [LAD] Attenuation of sounds in 3D space
        Date: Thu, 22 Jul 2010 14:51:00 +0200 
        [snip]
        Ambisonics is really every channel with the same priority and use-case. It 
        will not matter whether you use the set up with "front" at positiv-x direction 
        or 130° rotated around the z axis and 30° rotated around the x axis (when 
        using a full 3D rig). It will sound all the same. And the speakers in the room 
        have to be set up for this.
        Also the speakers are all supposed to be equally away from the listener for 
        best performance
        [snip]

IIUC 4 speakers could be set up in a quadrate with "front" at positiv-x
direction and the listener has to be in the middle of the quadrate.
Maybe there will be 8 similar speakers and amps, but regarding to the
sound card the limit is 8 channels. I guess somewhere on the ambisonics
website there will be some text and graphic about such setups.

- Ralf