Sound works for root and first user created, no one else
 

The title explains it all. In X, my sound works for both root (just logged into Gnome as root to test, not my normal operating procedure) and my main user. However, I tried to create a second user and that user has no sound. I get an error that no suitable device was found and it routes the sound to /dev/null. Some details:

Slack 9.1 (and loving it)
Dell Inspiron 4000
700MHZ
256MB RAM
ESS Maestro sound card
ATI Rage Mobility 8MB

Check your permissions on the sound devices. Your new user might not be a member of the group thats allowed to access the sound devices. The group is usually called audio. To add someone to that group type:

adduser theuser audio

Check your sound devices for the proper group for you:

ls -l /dev/dsp0

That did not work, but I did do chmod a+rw /dev/dsp0. Will that have the same effect?

It will be less secure, and their are other devices as well so you'd have to chmod them all which could get very risky. Their maybe other problems as well, depending on what sound system your using ( OSS/ALSA ) /dev/dsp may not actually be the device being used for sound.

If you look under /dev you'll see a lot of devices listed with the audio group. ( if thats what its called on your machine ).

There is no audio group on my machine and none of my groups seem to be audio.

So what group is either /dev/audio or /dev/dsp under? ( These maybe only links so find the group of what their linked too. )

Here is what I have right now:

So their assigned the group sys. Andy was your primary login. If you look at the permissions only andy is allowed access to the devices ( root is always allowed acces to everthing regardless ). you'll probably have too chmod g+rw audio* and chmod g+rw dsp* and add the new user to the sys group. This should get everthing working.

It rather annoying that the groups aren't set up for permissions to start with. Check your video permissions as well as OpenGL probably won't work for anyone but andy either.