Someone

josesito@josesito-pc:~$ xfce4-mixer
alsa: error: master control not found. I even tried to guess wildly, but to no avail.
alsa: info: developer information follows: (send E-Mail to Developer with that)
alsa: * Line,1  <--- hint hint
alsa: * Line,2  <--- hint hint
alsa: * Video,0  <--- hint hint
alsa: info: end of developer information
josesito@josesito-pc:~$