I got an onboard ALC 1200 realtek hight definition audio soundcard.
It's 7.1, but I dont have any 7.1 system.
I'd like to use it to ouput 2.0 to multiple sources.

I tried for example to plug my headset to the side suround speaker (it's a grey jack), but I dont get correct sound, since it's spacialized ...

Is there a way to have all speakers play the same 2.0 output ?
or even better, to play differents 2.0 output I could then tune (like volume / balance settings and mixing from differents sources, like line in or different applications ...)
Btw i'm running Vista 64

I don't have any 5.1 or 7.1 soundcard in this laptop with Vista, but i believe you should be able to find the options you look for by rigthclicking on the speaker icon in the systray, playback devices, and select configure (the left button).
Later, you can use the properties (the right button) to adjust the volumes of each output.

thanks for response

well in playback devices, I got
- HDMI digital (no clue what this is...)
- speakers
- realtek digital output (the SPDIF i suppose)
- realtek digital output (RCA) (no clue there etiher)

by cliking speakers, then configure, I can select from 2.0 to 7.1 speaker systems...
but this will produce 'spacialised' sound (rear speakers only play louds)

I'd like be able to set each speakers set (front,side and rear) as an independant output device. that could do the trick !
I'm begining to think of a software mixing table maybe...
any ideas on that ?

Generally no, at least under Windows consumer sound cards either present their output as 2 channel as as a single 5.1 or 7.1 output. Professional cards generally present pairs of stereo outputs.

i really doubt you could achieve that with onboard soundcard. in fact the only thing that can achieve this are profesional sound cards.
or audigy/sblive cards with kx drivers

Depending on what you want, it may be possible.

If you use a single application (like a Dj software), you can install ASIO4All, and you may be able to use the different pairs as independent inputs.

For the rest, the others already told you that commodity soundcards aren't thought to be used for multiple independent outputs.