Sound Troubleshooting Ubuntu
Open a terminal window.
sudo apt-get install pavucontrol
Now start pavucontrol and look how the tabs are. You start pavucontrol via the Fast Finder or via the terminal: you simply tap: pavucontrol (and press Enter).
pay attention: move the sliders do not all open at once, and no more than 90 % (deformation).
If this solution does not work, you can still offer the following solution.
Open a terminal window and displays the following command.
amixi -D pulse restrained Master 90%
Then, in the terminal,
-D pulse restrained Master on amixi
Now the sound should be at, on 90 % of the maximum volume.