My external USB speakers (logitech) started to fail (vibrating noise), so I got another pair of logitech external speakers (connector is the light green plug - not USB this time). When I plug headphones into both green audio jacks on my machine, I hear perfect sound. When I plug the new speakers into another computer, the speakers emit perfect sound.
So there does not appear to be a problem with my sound card, nor with the external speakers.
Clicking on the speaker icon in the top right -> sound settings -> sound, in the 'play sound through' box, no option exists for my external speakers. The two options are:
Digital Output (S/PDIF) Built-in Audio
Headphones Built-in Audio
and when I run aplay -l:
mybox:~$ aplay -l **** List of PLAYBACK Hardware Devices **** card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: Intel [HDA Intel], device 1: AD198x Digital [AD198x Digital] Subdevices: 1/1 Subdevice #0: subdevice #0
I have also tried rebooting with and without the speakers connected to the jack. Speakers are Logitech S-0152A.
Advice explaining how to resolve this issue would be greatly appreciated.
Update 2013-11-27 Speakers spontaneously started working - I didn't do anything. Now the sound card and speakers both play sound at the same time, but that issue has already been covered by another post in this forum and should be easy to fix.