Using headphone or back sound ports.

A recurring problem in Ubuntu is that you can only use one sound port at a time. For example, if you have your back output wired up to speakers and you plug in some headphones in the front, you'll get no sound.

The good news is that this can be easily fixed from a simple menu:

 

 It's easy to choose which port you want from a graphical menu

Click your volume control on the top panel and in the lis that appears click Sound Preferences. Navigate to the Output tab and you'll see a choice for the connector at the bottom. Simply choose the right connector and you're away!