I've been using fedora core 2 on a desktop shared by my family at home. In order to make it easy to use, I've set it up so that multiple X servers are running on vt7, vt8, etc. This is because AFAIK there's no functionality in GNOME that allows users to switch desktops without logging out as windoze allows. So, I take the memory hit and run multiple X servers. I've had great sound support under ALSA and my Creative Soundblaster card. I tested their capabilities by opening four audio streams at once and they were all mixed and sounded right. The problem I have is that multiple users cannot access the sound card at once. It appears that once one user logs into his X server (or runs an application that accesses /dev/dsp?) he takes control of the sound card and other users cannot access it.

I would like it so that I can switch between the multiple X servers and that control of the sound card can either be handed off between users or, best-case scenario, mixed with ongoing open sound streams. Right now, I have to log off the user who logged in first to relinquish control of the sound card and login again with the other user to hand control over. Any hacks or configuration information on how to set this up would be appreciated.

Cool setup can i do the same with kde ?
What you want is here. http://opensrc.org/alsa/index.php?page=DmixPlugin
That is a great howto.

Yeah, you should be able to do the same with any desktop environment. Just follow the instructions here. That's what I did. As for the dmix link, I took at look at it and it seems oriented towards mixing several sound streams at once. As I stated above, I can already do that as long as only one user is opening the multiple sound streams. It's when multiple users attempt this that it doesn't work for more than one user. This is more of an access control issue. I just don't know how to configure it.