Go to packages and search for alsamixer then when it all comes up you will see 5 programs i used Alsa mixer for Gnome then went to applications and pressed Gnome Alsa icon and clicked the mute buttons to off....Back to youtube and all is playing very good. Also if you cant play youtube vids go to Iceweasel addons and search for youtube flash video player 44.2 its the first one that comes up with a red icon install it...You can look in preferences for it under extensions and set it to html5 as i have it set or flash player both seem to work...Happy cracking lads