I have a Dell XPS13 9333 running Ubuntu 12.04. Speakers are working ok, while there are issues using headphones. Headphone are muted when there is no audio playing (that's ok), than when the audio starts playing (for example, a skype message arrives...but that is true for all kind of audio) I can hear a loud wave sound like in non tuned radios, which goes off a little bit later the audio stops playing.
Typing in terminal
sudo aplay -l
card 0: MID [HDA Intel MID], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: PCH [HDA Intel PCH], device 0: ALC668 Analog [ALC668 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0
Can you help me?