Set Sound Output

When I first installed Ubuntu onto a PC with an integrated audio device and tried to play a media file on a player, it had no sound. I tried these simple steps in setting Sound Preferences and then it had sound. It works for me for the audio device I have.

1. Go to System > Preferences > Sound to bring up the Sound Preferences window.
2. Under the Hardware tab, change Profile to Analog Stereo Duplex from the drop-down menu.
3. Under the Output tab, change Connector to Analog Output (LFE)/Amplifier from the drop-down menu.

As the items available from the drop-down menus might differ depending on the hardware devices detected by the system, you might want to try other items in the menus to see if they work for your devices. It might also help to check out the steps in Sound Troubleshooting from the Ubuntu Documentation.
Playing a media file in a proprietary format on a player might also have no sound if the required codecs are not installed. In this case, see Enable Media Playback in this article.