If you're using multiple sound sources, for example, Youtube, Skype, and MPlayer, all at the same time, you are going to run into problems with MPlayer because, by default, MPlayer tries to use OSS. With OSS, having multiple sound sources playing simultaneously is not possible because they lock the special file /dev/dsp. On the other hand, instructing MPlayer to use ALSA on every command line is cumbersome. Instead, edit MPlayer's configuration file ~/.mplayer/config and add the following property

ao=alsa

Tags: linux