I recently did a clean installation of Ubuntu 8.10. Everything went fine.

But with a clean installation it seems normal that some "codecs" or similar things have to be added for video and sound to work correctly.

So yesterday I wanted to see a news video and the normal sign came up saying I should install some more files. I did that, but then there was no sound. But I rebooted and the sound came back.

Today I simply have no sound. The alza mixer shows everything at 100%. I note though that when I open the volume control on the top left, it opens but will not close.

preferences/sound/sounds/soundevents has some 10 choices for playback. Some make the sound test freeze, others simply have no sound.

So the question: Is there a way to test the sound at the "machine" level just to make sure it is not a sound card problem? It seems to be OK (I forgot the names of the two commands I used to check it... got them from another question).

And if it is not the sound card, what should I look for or test?

A fairly new subject for me, so please don't assume anything on my part.

Many thanks,

Che José

Under system > preferences > sound, try changing everything to alsa and test it using the "test" button. Also, when you run alsamixer, in addition to moving the levels all the way up, make sure none of them are muted. If any of the levels are muted there will me a M at the bottom. Unmute it by pressing the M key on the keyboard.
If this doesn't help, try working your way through this sound troubleshooting guide:
http://ubuntuforums.org/showthread.php?t=205449

Thanks tommcd. Yes, I tried all the alternatives in preferences/sound, but no result.

I opened the link you suggested, and will work on it when I get a spare moment today. It looks like the writer knows what he is talking about.

So again, thanks.

José

Well, the mystery has deepened.

After my last posting I realized that system sounds seem to be OK. For example, opening and closing "Home folder" there is a little "beep".

But... for example, a music file using VLC, a Youtube video or even the
Skype test sound, all are zero.

So the sound system as such seems to be working OK, but is a certain class of sounds that do not function. Sounds more complicated to me, but that is why I turn to you folk for help!

The help page you suggested did not help me much I am afraid. Most of it does not apply to my specific problem.

Again, thanks.

José

try downloading gxine. configure sound to be sure volume is turn up. check your sound equaliser settings.