I am also a newbie to Ubuntu installed it just last week on my PC :) This helped me and I hope this helps you too ;)
Here is a snap of what my Unity GUI tells me about the Sound settings.
- Go to the sound Settings -> Press the super key / winkey (Ex-Windows user) and type sound.
- On the Output tab select the Headphones that is connected to the system.
- Un-mute and change the output volume value.
I use VLC player so I changed some settings over there and made it stick into the changelog.
- Open VLC Player
- Select Tools | Preferences from the menu.
- Open the Audio Tab and select All option at the bottom.This should result in a screen 'Advanced Preferences'.
- Change the Audio -> Output module to ALSA audio output.
- Save the setting - using the Save Button in the lower left of the Screen.
- Close the VLC Player (the setting will be applied the next time you open VLC)
- Open VLC Player and select Tools | Preferences | Audio | Output modules | ALSA
- If the USB Headphones you use are not in the list, then select the Refresh button.
- Select the USB Headphones you use from the list, then select the Save button.
I did tinker around with a few other commands that I found here (link1, link2, link3)
Truth be told I am a newbie to this place and this is my first answer. I hope I helped at least a bit ＿φ(°-°=)