I've looked around for a solution for my problem in other threads but nothing seems to work.

I'm running a Mandrake 9.1 system. While waiting for a new monitor to come I connected an old 14" to my box just so that I could play some mp3's from the command line. I was playing mp3's using mpg123 (and all was fine) then decided to suspend playback by hitting ctrl+z. About an hour later I returned and fg'ed my mpg123 app and it happily continued running, but no sound came from my speakers.

To help narrow down the problem I rebooted under windows - sound works fine. I then rebooted under linux and tried starting WindowMaker and playing some mp3's using xmms - still no sound (yet the equalizer shows that there is music playing).

What's wrong? Why would I lose sound after suspending a mpg123 process?

Please help!

I once "lost sound" on my Linux system, but I "found" it again by running aumix and turing up the main volume control. I'm not sure how it got turned down in the first place, but that fixed my problem.

Nope, I tried that before posting here. I've tried both aumix and alsamixer and neither make any difference.

lsof|grep dsp
if this shows a process (probably artsd), kill process and test.
play /usr/share/sounds/KDE_Error.wav is a simple test

lsof | grep dsp
didn't come back with anything, and when trying playing a wav file still nothing is heard.

check dmesg to see your soundcard is recognized.

i am not sure if /dev/dsp is used for all sound boards. If you have strace and are root, you can try:
strace -f play /usr/share/sounds/KDE_Error.wav 2>&1|grep "open.*dev"

On my box, this includes:
open("/dev/dsp", O_WRONLY ...

if /dev/dsp, try
cat /usr/share/sounds/KDE_Error.wav>/dev/dsp

if no sound, volume has been set low - I use KMix to adjust.

If you are using ALSA, you may want to add dmix in your .asoundrc so you can use other sound programs at the same time.

Try going into Mandrake Control Center and turn off the sound and ALSA. Then turn them on again.

You must have accidently mute the master volume or the PCM volume.

I also use Kmix to adjust my sound settings. Don't forget to click on save as defaults settings when you are done setting the volumes.

Thanks for the help so far, but still no joy.

When trying:

strace -f play /usr/share/sounds/KDE_Error.wav 2>&1|grep "open.*dev"

I get the following:

[pid 4767] open("/dev/tty", O_RDWR|O_NONBLOCK|O_LARGEFILE) = -1 ENXIO (No such device or address)
[pid 4767] open("/dev/pts/1", O_RDWR|O_NONBLOCK|O_LARGEFILE) = 5
[pid 4767] open("/dev/dsp", O_WRONLY|O_NONBLOCK) = 7

When trying:

cat /usr/share/sounds/KDE_Error.wav>/dev/dsp

I can hear white noise from the speakers (like suddenly they were turned up very loud but not playing anything) but no sound. I tried out kmix and found that no channels were muted, and all volumes were turned up. And something seems to be working as the static from the previous command would get louder/softer as I moved the PCM volume up and down.

Are we getting closer?

Oh, also I tried turning ALSA and sound on and off in the mandrake control panel but there was no change.