Thank you for your reply.

Volume levels seems to be correctly tuned after checking in the GUI Gnome sound configurator.
The sound does work when speakers are plugged on the front side and selecting 'NVidia CK804 (ALSA mixer)' in the sound-configurator of Gnome. But only the right side work, the left one hardly does. Ihave checked the wire and it's OK (both sides work when plugged to a stereo radio).

Plugging the speakers on the rear side and selecting the sound card 'realtek ALC850 R0 (OSS sound mixer)' in the GUI sound configurator of Gnome gives this message when I select the 'test' :
audiotestsrc wave=sine freq=512 ! audioconvert ! audioresample ! gconfaudiosink: Could not open audio device for playback. Device is being used by another application.
And when i select 'Automatic detection' of the sound card, the test gives an extremely weak sound (but on both sides this time), hardly earable when speaker are turned at maximum.

So, plugged on the rear-side , the speakers still don't make any correctly earable sound. And plugged on front-side only left speaker works correctly althought wire and speakers are OK.


What do you think about it ? Maybe is there a file to edit ..?

Thank you for replying me.

Have a nice day.