OK, I'm a bit embarrassed to ask such a basic question but given I have a history of stupid questions, here is another one:

Does s3D Audio work ?

Let me get into the scenario a bit:
I want to have a game (same goes for a movie scene as well) where the source of the sound and the sound would be placed near perfectly in the virtual set.
If I would look into a virtual s3D box with my screen as the front of the box and the scene being inside the box (lets assume the boxes depth is the same as the width of the screen) I would want to recognize if a bouncing ball bounces in the lower left corner at the back of the box or if it bounces in the middle close to the screen.

My general question would be, how precise would and what kind of system (stereo, 5.1, 7.1++) would you need for it to work under the premise that the s3d scene is behind the screen (no pup out)

Now here are some things that confused me:

Size of the screen:
If I compare a s3D 20''computer monitor and a 60''screen for a projector, they would obviously produce different sized virtual boxes. If I place both in the same room with my audio-system, wouldn't the audio system have to need to know how big the box is in order to project the virtual sound correctly "behind" the screen ?

Convergence/ depth settings:
If the user can adjust the depth and convergence settings and by that kind of "relocating" the geometry, wouldn't the audio system need to know that as well, especially if pop out would be allowed ?

In fact you just need good made stereo Headset. take a shot:
http://www.youtube.com/watch?v=0M6SELmKn1w

Audio system are already processing the 3D position of sound source

Ego shooters take your position for processing the sound, moving it to screen depth would result in a feeling that your ears are behind your head.

Many 3rd person games take the Camera position as hearing spot, that would be also it for your bouncing box...

I think the most of the distance is percept by loudness only the direction by run length/time difference between ears.

To your Positioning problem: Ask the user for viewing distance and read out the separation of and example object and then work with the z-buffer

You mean stereo sound? Been around for ages. Probably 5.1 would be enough for what you are talking about. However this is usually set up to have you be the center of the action (where else would you want to be?). If you needed a box behind the monitor then place the speakers behind the monitor.

Hi there,

thanx for the replies so far, it clarified a lot of things on how stuff works technically at the moment.
Especially the issue about the camera position beeing the hearing spot in 3rd person games and the 1st person "center of the action" position gave me further food for tought.

ATM I would think of using a stereo headset plus tracking the users position in relation to the screen to place the hearing spot correctly.
Problematic would be indeed that most middleware would bind the listening spot to the camera wich won't be realistic in a stereoscopic setting.

I don't think true s3d audio is doable at this time, you would need binaural sound synthesis in realtime to achieve that. You'd have to calculate reverberations and interactions between the environnement, the ears and each sound source. And it would only work with headphones and only for one specific listener, since the outer ear form factor is specific to each person.

Still, using OpenAL and probably similar libraries you can define several parameters for the listener like position, orientation and velocity (to account for the Doppler effect). And it does also seem to support¹ the Bauer stereophonic-to-binaural DSP² which should be helpful when using headphones.

¹ http://connect.creativelabs.com/openal/ ... 1760F0364A
² http://bs2b.sourceforge.net/