mmm

Excuse for inconvenience.

Jopopo say correct:
[quote] i'm not used to lxde, on xfce every running app that produces sound is listed there and every apps' volume and output can be adjusted separately from here too[/quote]

In Lubuntu not there is a panel for control volume in every applications (app).
There is a button of volume (General) and was always 100%.
So Fafhrd suggest me for install [b]pavucontrol[/b].
[center]sudo apt-get install pavucontrol[/center]
[center]pavucontrol[/center]
Now we have a program with every setting in input devices , output devices and volume for everyin apps.

So I launch Nexuiz-sdl and fixed that was mute in this application.
Is bizarre, I know but but it can happen to you too.

So thanks Fafhrd and also Kga that it suggest alternative launches of Nexuiz.